diff --git a/cmd/event-received/sirius_event_handler.go b/cmd/event-received/sirius_event_handler.go
index 7a66799c49..ba9f7033bf 100644
--- a/cmd/event-received/sirius_event_handler.go
+++ b/cmd/event-received/sirius_event_handler.go
@@ -16,6 +16,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/lpastore"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/pay"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/sharecode"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/task"
 )
@@ -231,16 +232,27 @@ func handleDonorSubmissionCompleted(ctx context.Context, client dynamodbClient,
 	lpaID := uuidString()
 
 	donor := &donordata.Provided{
-		PK:        dynamo.LpaKey(lpaID),
-		SK:        dynamo.LpaOwnerKey(dynamo.DonorKey("PAPER")),
-		LpaID:     lpaID,
-		LpaUID:    v.UID,
-		CreatedAt: now(),
-		Version:   1,
+		PK:                           dynamo.LpaKey(lpaID),
+		SK:                           dynamo.LpaOwnerKey(dynamo.DonorKey("PAPER")),
+		LpaID:                        lpaID,
+		LpaUID:                       v.UID,
+		CreatedAt:                    now(),
+		Version:                      1,
+		CertificateProviderInvitedAt: now(),
 	}
 
 	transaction := dynamo.NewTransaction().
 		Create(donor).
+		Create(scheduled.Event{
+			PK:                dynamo.ScheduledDayKey(donor.CertificateProviderInvitedAt.AddDate(0, 3, 0)),
+			SK:                dynamo.ScheduledKey(donor.CertificateProviderInvitedAt.AddDate(0, 3, 0), int(scheduled.ActionRemindCertificateProviderToComplete)),
+			CreatedAt:         now(),
+			At:                donor.CertificateProviderInvitedAt.AddDate(0, 3, 0),
+			Action:            scheduled.ActionRemindCertificateProviderToComplete,
+			TargetLpaKey:      donor.PK,
+			TargetLpaOwnerKey: donor.SK,
+			LpaUID:            donor.LpaUID,
+		}).
 		Create(dynamo.Keys{PK: dynamo.UIDKey(v.UID), SK: dynamo.MetadataKey("")}).
 		Create(dynamo.Keys{PK: donor.PK, SK: dynamo.ReservedKey(dynamo.DonorKey)})
 
diff --git a/cmd/event-received/sirius_event_handler_test.go b/cmd/event-received/sirius_event_handler_test.go
index 916808ee0e..e2c18c8839 100644
--- a/cmd/event-received/sirius_event_handler_test.go
+++ b/cmd/event-received/sirius_event_handler_test.go
@@ -20,6 +20,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/lpastore/lpadata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/pay"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/sharecode"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/task"
 	"github.com/stretchr/testify/assert"
@@ -756,12 +757,23 @@ func TestHandleDonorSubmissionCompleted(t *testing.T) {
 		WriteTransaction(ctx, &dynamo.Transaction{
 			Creates: []any{
 				&donordata.Provided{
-					PK:        dynamo.LpaKey(testUuidString),
-					SK:        dynamo.LpaOwnerKey(dynamo.DonorKey("PAPER")),
-					LpaID:     testUuidString,
-					LpaUID:    "M-1111-2222-3333",
-					CreatedAt: testNow,
-					Version:   1,
+					PK:                           dynamo.LpaKey(testUuidString),
+					SK:                           dynamo.LpaOwnerKey(dynamo.DonorKey("PAPER")),
+					LpaID:                        testUuidString,
+					LpaUID:                       "M-1111-2222-3333",
+					CreatedAt:                    testNow,
+					Version:                      1,
+					CertificateProviderInvitedAt: testNow,
+				},
+				scheduled.Event{
+					PK:                dynamo.ScheduledDayKey(testNow.AddDate(0, 3, 0)),
+					SK:                dynamo.ScheduledKey(testNow.AddDate(0, 3, 0), int(scheduled.ActionRemindCertificateProviderToComplete)),
+					CreatedAt:         testNow,
+					At:                testNow.AddDate(0, 3, 0),
+					Action:            scheduled.ActionRemindCertificateProviderToComplete,
+					TargetLpaKey:      dynamo.LpaKey(testUuidString),
+					TargetLpaOwnerKey: dynamo.LpaOwnerKey(dynamo.DonorKey("PAPER")),
+					LpaUID:            "M-1111-2222-3333",
 				},
 				dynamo.Keys{PK: dynamo.UIDKey("M-1111-2222-3333"), SK: dynamo.MetadataKey("")},
 				dynamo.Keys{PK: dynamo.LpaKey(testUuidString), SK: dynamo.ReservedKey(dynamo.DonorKey)},
diff --git a/cmd/schedule-runner/main.go b/cmd/schedule-runner/main.go
index 370c09608c..23b3de0ff8 100644
--- a/cmd/schedule-runner/main.go
+++ b/cmd/schedule-runner/main.go
@@ -13,6 +13,7 @@ import (
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/service/cloudwatch"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/certificateprovider"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/dynamo"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/event"
@@ -81,8 +82,9 @@ func handleRunSchedule(ctx context.Context) error {
 		return err
 	}
 
-	donorStore := donor.NewStore(dynamoClient, eventClient, logger, searchClient)
 	scheduledStore := scheduled.NewStore(dynamoClient)
+	donorStore := donor.NewStore(dynamoClient, eventClient, logger, searchClient)
+	certificateProviderStore := certificateprovider.NewStore(dynamoClient)
 
 	if Tag == "" {
 		Tag = os.Getenv("TAG")
@@ -91,7 +93,7 @@ func handleRunSchedule(ctx context.Context) error {
 	client := cloudwatch.NewFromConfig(cfg)
 	metricsClient := telemetry.NewMetricsClient(client, Tag)
 
-	runner := scheduled.NewRunner(logger, scheduledStore, donorStore, notifyClient, metricsClient, metricsEnabled)
+	runner := scheduled.NewRunner(logger, scheduledStore, donorStore, certificateProviderStore, notifyClient, bundle, metricsClient, metricsEnabled)
 
 	if err = runner.Run(ctx); err != nil {
 		logger.Error("runner error", slog.Any("err", err))
diff --git a/internal/certificateprovider/store.go b/internal/certificateprovider/store.go
index f38ee08ed8..99676f71dd 100644
--- a/internal/certificateprovider/store.go
+++ b/internal/certificateprovider/store.go
@@ -93,8 +93,12 @@ func (s *Store) GetAny(ctx context.Context) (*certificateproviderdata.Provided,
 		return nil, errors.New("certificateProviderStore.GetAny requires LpaID")
 	}
 
+	return s.One(ctx, dynamo.LpaKey(data.LpaID))
+}
+
+func (s *Store) One(ctx context.Context, pk dynamo.LpaKeyType) (*certificateproviderdata.Provided, error) {
 	var certificateProvider certificateproviderdata.Provided
-	err = s.dynamoClient.OneByPartialSK(ctx, dynamo.LpaKey(data.LpaID), dynamo.CertificateProviderKey(""), &certificateProvider)
+	err := s.dynamoClient.OneByPartialSK(ctx, pk, dynamo.CertificateProviderKey(""), &certificateProvider)
 
 	return &certificateProvider, err
 }
diff --git a/internal/donor/donordata/provided.go b/internal/donor/donordata/provided.go
index 3db592eba4..bf90c4ade3 100644
--- a/internal/donor/donordata/provided.go
+++ b/internal/donor/donordata/provided.go
@@ -165,6 +165,10 @@ type Provided struct {
 	// for, if applying for a repeat of an LPA with reference prefixed M.
 	CostOfRepeatApplication pay.CostOfRepeatApplication
 
+	// CertificateProviderInvitedAt records when the invite is sent to the
+	// certificate provider to act.
+	CertificateProviderInvitedAt time.Time
+
 	HasSentApplicationUpdatedEvent bool `hash:"-"`
 }
 
@@ -218,7 +222,8 @@ func (c toCheck) HashInclude(field string, _ any) (bool, error) {
 		"WantVoucher",
 		"Voucher",
 		"FailedVouchAttempts",
-		"CostOfRepeatApplication":
+		"CostOfRepeatApplication",
+		"CertificateProviderInvitedAt":
 		return false, nil
 	}
 
@@ -294,6 +299,19 @@ func (p *Provided) CourtOfProtectionSubmissionDeadline() time.Time {
 	return p.SignedAt.AddDate(0, 6, 0)
 }
 
+// ExpiresAt gives the date the LPA expires.
+func (p *Provided) ExpiresAt() time.Time {
+	if p.DonorIdentityConfirmed() && !p.WitnessedByCertificateProviderAt.IsZero() {
+		return p.SignedAt.AddDate(0, 24, 0)
+	}
+
+	if !p.SignedAt.IsZero() {
+		return p.SignedAt.AddDate(0, 6, 0)
+	}
+
+	return time.Time{}
+}
+
 type Under18ActorDetails struct {
 	FullName    string
 	DateOfBirth date.Date
diff --git a/internal/donor/donordata/provided_test.go b/internal/donor/donordata/provided_test.go
index 91fce93f94..e0e6afb9ec 100644
--- a/internal/donor/donordata/provided_test.go
+++ b/internal/donor/donordata/provided_test.go
@@ -42,14 +42,14 @@ func TestGenerateHash(t *testing.T) {
 	}
 
 	// DO change this value to match the updates
-	const modified uint64 = 0x42eaf05fa4af6121
+	const modified uint64 = 0xed86effa3514f49d
 
 	// DO NOT change these initial hash values. If a field has been added/removed
 	// you will need to handle the version gracefully by modifying
 	// (*Provided).HashInclude and adding another testcase for the new
 	// version.
 	testcases := map[uint8]uint64{
-		0: 0xe929f7d694b60743,
+		0: 0xfcc0efdd2824800c,
 	}
 
 	for version, initial := range testcases {
diff --git a/internal/donor/donorpage/check_your_lpa.go b/internal/donor/donorpage/check_your_lpa.go
index c02d161c73..ea851de505 100644
--- a/internal/donor/donorpage/check_your_lpa.go
+++ b/internal/donor/donorpage/check_your_lpa.go
@@ -3,6 +3,7 @@ package donorpage
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/http"
 	"net/url"
 	"time"
@@ -15,6 +16,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/localize"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/page"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/sharecode"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/task"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/validation"
@@ -33,7 +35,9 @@ type checkYourLpaNotifier struct {
 	notifyClient             NotifyClient
 	shareCodeSender          ShareCodeSender
 	certificateProviderStore CertificateProviderStore
+	scheduledStore           ScheduledStore
 	appPublicURL             string
+	now                      func() time.Time
 }
 
 func (n *checkYourLpaNotifier) Notify(ctx context.Context, appData appcontext.Data, donor *donordata.Provided, wasCompleted bool) error {
@@ -66,6 +70,18 @@ func (n *checkYourLpaNotifier) sendPaperNotification(ctx context.Context, appDat
 
 func (n *checkYourLpaNotifier) sendOnlineNotification(ctx context.Context, appData appcontext.Data, donor *donordata.Provided, wasCompleted bool) error {
 	if !wasCompleted {
+		donor.CertificateProviderInvitedAt = n.now()
+
+		if err := n.scheduledStore.Create(ctx, scheduled.Event{
+			At:                donor.CertificateProviderInvitedAt.AddDate(0, 3, 0),
+			Action:            scheduled.ActionRemindCertificateProviderToComplete,
+			TargetLpaKey:      donor.PK,
+			TargetLpaOwnerKey: donor.SK,
+			LpaUID:            donor.LpaUID,
+		}); err != nil {
+			return fmt.Errorf("could not schedule certificate provider prompt: %w", err)
+		}
+
 		return n.shareCodeSender.SendCertificateProviderInvite(ctx, appData, sharecode.CertificateProviderInvite{
 			LpaKey:                      donor.PK,
 			LpaOwnerKey:                 donor.SK,
@@ -101,12 +117,14 @@ func (n *checkYourLpaNotifier) sendOnlineNotification(ctx context.Context, appDa
 	return n.notifyClient.SendActorSMS(ctx, notify.ToProvidedCertificateProvider(certificateProvider, donor.CertificateProvider), donor.LpaUID, sms)
 }
 
-func CheckYourLpa(tmpl template.Template, donorStore DonorStore, shareCodeSender ShareCodeSender, notifyClient NotifyClient, certificateProviderStore CertificateProviderStore, now func() time.Time, appPublicURL string) Handler {
+func CheckYourLpa(tmpl template.Template, donorStore DonorStore, shareCodeSender ShareCodeSender, notifyClient NotifyClient, certificateProviderStore CertificateProviderStore, scheduledStore ScheduledStore, now func() time.Time, appPublicURL string) Handler {
 	notifier := &checkYourLpaNotifier{
 		notifyClient:             notifyClient,
 		shareCodeSender:          shareCodeSender,
 		certificateProviderStore: certificateProviderStore,
 		appPublicURL:             appPublicURL,
+		now:                      now,
+		scheduledStore:           scheduledStore,
 	}
 
 	return func(appData appcontext.Data, w http.ResponseWriter, r *http.Request, provided *donordata.Provided) error {
diff --git a/internal/donor/donorpage/check_your_lpa_test.go b/internal/donor/donorpage/check_your_lpa_test.go
index 7d99412749..961cfd3a0c 100644
--- a/internal/donor/donorpage/check_your_lpa_test.go
+++ b/internal/donor/donorpage/check_your_lpa_test.go
@@ -15,6 +15,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/lpastore/lpadata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/page"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/sharecode"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/task"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/validation"
@@ -36,7 +37,7 @@ func TestGetCheckYourLpa(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{})
+	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{})
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -64,7 +65,7 @@ func TestGetCheckYourLpaFromStore(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
+	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -100,7 +101,7 @@ func TestPostCheckYourLpaWhenNotChanged(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
+	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -132,11 +133,12 @@ func TestPostCheckYourLpaDigitalCertificateProviderOnFirstCheck(t *testing.T) {
 			}
 
 			updatedDonor := &donordata.Provided{
-				LpaID:               "lpa-id",
-				Hash:                5,
-				CheckedAt:           testNow,
-				Tasks:               donordata.Tasks{CheckYourLpa: task.StateCompleted},
-				CertificateProvider: donordata.CertificateProvider{UID: uid, FirstNames: "John", LastName: "Smith", Email: "john@example.com", CarryOutBy: lpadata.ChannelOnline},
+				LpaID:                        "lpa-id",
+				Hash:                         5,
+				CheckedAt:                    testNow,
+				Tasks:                        donordata.Tasks{CheckYourLpa: task.StateCompleted},
+				CertificateProvider:          donordata.CertificateProvider{UID: uid, FirstNames: "John", LastName: "Smith", Email: "john@example.com", CarryOutBy: lpadata.ChannelOnline},
+				CertificateProviderInvitedAt: testNow,
 			}
 			updatedDonor.UpdateCheckedHash()
 
@@ -148,12 +150,23 @@ func TestPostCheckYourLpaDigitalCertificateProviderOnFirstCheck(t *testing.T) {
 				}, notify.ToCertificateProvider(provided.CertificateProvider)).
 				Return(nil)
 
+			scheduledStore := newMockScheduledStore(t)
+			scheduledStore.EXPECT().
+				Create(r.Context(), scheduled.Event{
+					At:                updatedDonor.CertificateProviderInvitedAt.AddDate(0, 3, 0),
+					Action:            scheduled.ActionRemindCertificateProviderToComplete,
+					TargetLpaKey:      updatedDonor.PK,
+					TargetLpaOwnerKey: updatedDonor.SK,
+					LpaUID:            updatedDonor.LpaUID,
+				}).
+				Return(nil)
+
 			donorStore := newMockDonorStore(t)
 			donorStore.EXPECT().
 				Put(r.Context(), updatedDonor).
 				Return(nil)
 
-			err := CheckYourLpa(nil, donorStore, shareCodeSender, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
+			err := CheckYourLpa(nil, donorStore, shareCodeSender, nil, nil, scheduledStore, testNowFn, "http://example.org")(testAppData, w, r, provided)
 			resp := w.Result()
 
 			assert.Nil(t, err)
@@ -245,7 +258,7 @@ func TestPostCheckYourLpaDigitalCertificateProviderOnSubsequentChecks(t *testing
 				GetAny(r.Context()).
 				Return(certificateProvider, nil)
 
-			err := CheckYourLpa(nil, donorStore, nil, notifyClient, certificateProviderStore, testNowFn, "http://example.org")(testAppData, w, r, provided)
+			err := CheckYourLpa(nil, donorStore, nil, notifyClient, certificateProviderStore, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
 			resp := w.Result()
 
 			assert.Nil(t, err)
@@ -269,7 +282,7 @@ func TestPostCheckYourLpaDigitalCertificateProviderOnSubsequentChecksCertificate
 		GetAny(r.Context()).
 		Return(nil, expectedError)
 
-	err := CheckYourLpa(nil, nil, nil, nil, certificateProviderStore, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{
+	err := CheckYourLpa(nil, nil, nil, nil, certificateProviderStore, nil, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{
 		LpaID:               "lpa-id",
 		Hash:                5,
 		Type:                lpadata.LpaTypePropertyAndAffairs,
@@ -336,7 +349,7 @@ func TestPostCheckYourLpaPaperCertificateProviderOnFirstCheck(t *testing.T) {
 				}).
 				Return(nil)
 
-			err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
+			err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
 			resp := w.Result()
 
 			assert.Nil(t, err)
@@ -380,7 +393,7 @@ func TestPostCheckYourLpaPaperCertificateProviderOnSubsequentCheck(t *testing.T)
 		}).
 		Return(nil)
 
-	err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
+	err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, provided)
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -418,13 +431,37 @@ func TestPostCheckYourLpaWhenStoreErrors(t *testing.T) {
 		Put(r.Context(), mock.Anything).
 		Return(expectedError)
 
-	err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
+	err := CheckYourLpa(nil, donorStore, nil, notifyClient, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
 	resp := w.Result()
 
 	assert.Equal(t, expectedError, err)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 }
 
+func TestPostCheckYourLpaWhenScheduledStoreErrors(t *testing.T) {
+	form := url.Values{
+		"checked-and-happy": {"1"},
+	}
+
+	w := httptest.NewRecorder()
+	r, _ := http.NewRequest(http.MethodPost, "/", strings.NewReader(form.Encode()))
+	r.Header.Add("Content-Type", page.FormUrlEncoded)
+
+	donor := &donordata.Provided{
+		LpaID: "lpa-id",
+		Hash:  5,
+		Tasks: donordata.Tasks{CheckYourLpa: task.StateInProgress},
+	}
+
+	scheduledStore := newMockScheduledStore(t)
+	scheduledStore.EXPECT().
+		Create(mock.Anything, mock.Anything).
+		Return(expectedError)
+
+	err := CheckYourLpa(nil, nil, nil, nil, nil, scheduledStore, testNowFn, "http://example.org")(testAppData, w, r, donor)
+	assert.ErrorIs(t, err, expectedError)
+}
+
 func TestPostCheckYourLpaWhenShareCodeSenderErrors(t *testing.T) {
 	form := url.Values{
 		"checked-and-happy": {"1"},
@@ -440,12 +477,17 @@ func TestPostCheckYourLpaWhenShareCodeSenderErrors(t *testing.T) {
 		Tasks: donordata.Tasks{CheckYourLpa: task.StateInProgress},
 	}
 
+	scheduledStore := newMockScheduledStore(t)
+	scheduledStore.EXPECT().
+		Create(mock.Anything, mock.Anything).
+		Return(nil)
+
 	shareCodeSender := newMockShareCodeSender(t)
 	shareCodeSender.EXPECT().
 		SendCertificateProviderInvite(r.Context(), testAppData, mock.Anything, mock.Anything).
 		Return(expectedError)
 
-	err := CheckYourLpa(nil, nil, shareCodeSender, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, donor)
+	err := CheckYourLpa(nil, nil, shareCodeSender, nil, nil, scheduledStore, testNowFn, "http://example.org")(testAppData, w, r, donor)
 	resp := w.Result()
 
 	assert.Equal(t, expectedError, err)
@@ -473,7 +515,7 @@ func TestPostCheckYourLpaWhenNotifyClientErrors(t *testing.T) {
 		SendActorSMS(mock.Anything, mock.Anything, mock.Anything, mock.Anything).
 		Return(expectedError)
 
-	err := CheckYourLpa(nil, nil, nil, notifyClient, nil, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{Hash: 5, CertificateProvider: donordata.CertificateProvider{CarryOutBy: lpadata.ChannelPaper}})
+	err := CheckYourLpa(nil, nil, nil, notifyClient, nil, nil, testNowFn, "http://example.org")(testAppData, w, r, &donordata.Provided{Hash: 5, CertificateProvider: donordata.CertificateProvider{CarryOutBy: lpadata.ChannelPaper}})
 	resp := w.Result()
 
 	assert.Equal(t, expectedError, err)
@@ -496,7 +538,7 @@ func TestPostCheckYourLpaWhenValidationErrors(t *testing.T) {
 		})).
 		Return(nil)
 
-	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, nil, "http://example.org")(testAppData, w, r, &donordata.Provided{Hash: 5})
+	err := CheckYourLpa(template.Execute, nil, nil, nil, nil, nil, nil, "http://example.org")(testAppData, w, r, &donordata.Provided{Hash: 5})
 	resp := w.Result()
 
 	assert.Nil(t, err)
diff --git a/internal/donor/donorpage/identity_with_one_login_callback.go b/internal/donor/donorpage/identity_with_one_login_callback.go
index 04be5266fa..97b04e3130 100644
--- a/internal/donor/donorpage/identity_with_one_login_callback.go
+++ b/internal/donor/donorpage/identity_with_one_login_callback.go
@@ -81,7 +81,7 @@ func IdentityWithOneLoginCallback(oneLoginClient OneLoginClient, sessionStore Se
 			return donor.PathUnableToConfirmIdentity.Redirect(w, r, appData, provided)
 		default:
 			if err := scheduledStore.Create(r.Context(), scheduled.Event{
-				At:                userData.CheckedAt.AddDate(0, 6, 0),
+				At:                scheduled.ExpireDonorIdentityAt(userData.CheckedAt),
 				Action:            scheduled.ActionExpireDonorIdentity,
 				TargetLpaKey:      provided.PK,
 				TargetLpaOwnerKey: provided.SK,
diff --git a/internal/donor/donorpage/register.go b/internal/donor/donorpage/register.go
index 03f1b0a92e..2d2922d0d0 100644
--- a/internal/donor/donorpage/register.go
+++ b/internal/donor/donorpage/register.go
@@ -356,7 +356,7 @@ func Register(
 	handleWithDonor(donor.PathConfirmYourCertificateProviderIsNotRelated, page.CanGoBack,
 		ConfirmYourCertificateProviderIsNotRelated(tmpls.Get("confirm_your_certificate_provider_is_not_related.gohtml"), donorStore, time.Now))
 	handleWithDonor(donor.PathCheckYourLpa, page.CanGoBack,
-		CheckYourLpa(tmpls.Get("check_your_lpa.gohtml"), donorStore, shareCodeSender, notifyClient, certificateProviderStore, time.Now, appPublicURL))
+		CheckYourLpa(tmpls.Get("check_your_lpa.gohtml"), donorStore, shareCodeSender, notifyClient, certificateProviderStore, scheduledStore, time.Now, appPublicURL))
 	handleWithDonor(donor.PathLpaDetailsSaved, page.CanGoBack,
 		LpaDetailsSaved(tmpls.Get("lpa_details_saved.gohtml")))
 
@@ -442,9 +442,9 @@ func Register(
 	handleWithDonor(donor.PathLpaYourLegalRightsAndResponsibilities, page.CanGoBack,
 		Guidance(tmpls.Get("your_legal_rights_and_responsibilities.gohtml")))
 	handleWithDonor(donor.PathSignYourLpa, page.CanGoBack,
-		SignYourLpa(tmpls.Get("sign_your_lpa.gohtml"), donorStore, time.Now))
+		SignYourLpa(tmpls.Get("sign_your_lpa.gohtml"), donorStore, scheduledStore, time.Now))
 	handleWithDonor(donor.PathSignTheLpaOnBehalf, page.CanGoBack,
-		SignYourLpa(tmpls.Get("sign_the_lpa_on_behalf.gohtml"), donorStore, time.Now))
+		SignYourLpa(tmpls.Get("sign_the_lpa_on_behalf.gohtml"), donorStore, scheduledStore, time.Now))
 	handleWithDonor(donor.PathWitnessingYourSignature, page.None,
 		WitnessingYourSignature(tmpls.Get("witnessing_your_signature.gohtml"), witnessCodeSender, donorStore))
 	handleWithDonor(donor.PathWitnessingAsIndependentWitness, page.None,
diff --git a/internal/donor/donorpage/sign_your_lpa.go b/internal/donor/donorpage/sign_your_lpa.go
index ba767cfb7b..fa28ec613b 100644
--- a/internal/donor/donorpage/sign_your_lpa.go
+++ b/internal/donor/donorpage/sign_your_lpa.go
@@ -1,6 +1,7 @@
 package donorpage
 
 import (
+	"fmt"
 	"net/http"
 	"time"
 
@@ -8,6 +9,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/appcontext"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor/donordata"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/validation"
 )
 
@@ -25,7 +27,7 @@ const (
 	WantToApplyForLpa = "want-to-apply"
 )
 
-func SignYourLpa(tmpl template.Template, donorStore DonorStore, now func() time.Time) Handler {
+func SignYourLpa(tmpl template.Template, donorStore DonorStore, scheduledStore ScheduledStore, now func() time.Time) Handler {
 	return func(appData appcontext.Data, w http.ResponseWriter, r *http.Request, provided *donordata.Provided) error {
 		if !provided.SignedAt.IsZero() {
 			return donor.PathWitnessingYourSignature.Redirect(w, r, appData, provided)
@@ -51,6 +53,16 @@ func SignYourLpa(tmpl template.Template, donorStore DonorStore, now func() time.
 				provided.WantToSignLpa = data.Form.WantToSign
 				provided.SignedAt = now()
 
+				if err := scheduledStore.Create(r.Context(), scheduled.Event{
+					At:                provided.SignedAt.AddDate(0, 3, 0),
+					Action:            scheduled.ActionRemindCertificateProviderToComplete,
+					TargetLpaKey:      provided.PK,
+					TargetLpaOwnerKey: provided.SK,
+					LpaUID:            provided.LpaUID,
+				}); err != nil {
+					return fmt.Errorf("could not schedule certificate provider prompt: %w", err)
+				}
+
 				if err := donorStore.Put(r.Context(), provided); err != nil {
 					return err
 				}
diff --git a/internal/donor/donorpage/sign_your_lpa_test.go b/internal/donor/donorpage/sign_your_lpa_test.go
index e1e8dd947d..77fe433cc7 100644
--- a/internal/donor/donorpage/sign_your_lpa_test.go
+++ b/internal/donor/donorpage/sign_your_lpa_test.go
@@ -12,6 +12,7 @@ import (
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor/donordata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/identity"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/page"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/scheduled"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/validation"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
@@ -32,7 +33,7 @@ func TestGetSignYourLpa(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := SignYourLpa(template.Execute, nil, testNowFn)(testAppData, w, r, &donordata.Provided{})
+	err := SignYourLpa(template.Execute, nil, nil, testNowFn)(testAppData, w, r, &donordata.Provided{})
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -43,7 +44,7 @@ func TestGetSignYourLpaWhenSigned(t *testing.T) {
 	w := httptest.NewRecorder()
 	r, _ := http.NewRequest(http.MethodGet, "/", nil)
 
-	err := SignYourLpa(nil, nil, testNowFn)(testAppData, w, r, &donordata.Provided{
+	err := SignYourLpa(nil, nil, nil, testNowFn)(testAppData, w, r, &donordata.Provided{
 		LpaID:            "lpa-id",
 		IdentityUserData: identity.UserData{Status: identity.StatusConfirmed},
 		SignedAt:         time.Now(),
@@ -78,7 +79,7 @@ func TestGetSignYourLpaFromStore(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := SignYourLpa(template.Execute, nil, testNowFn)(testAppData, w, r, donor)
+	err := SignYourLpa(template.Execute, nil, nil, testNowFn)(testAppData, w, r, donor)
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -105,7 +106,15 @@ func TestPostSignYourLpa(t *testing.T) {
 		}).
 		Return(nil)
 
-	err := SignYourLpa(nil, donorStore, testNowFn)(testAppData, w, r, &donordata.Provided{LpaID: "lpa-id", IdentityUserData: identity.UserData{Status: identity.StatusConfirmed}})
+	scheduledStore := newMockScheduledStore(t)
+	scheduledStore.EXPECT().
+		Create(r.Context(), scheduled.Event{
+			At:     testNow.AddDate(0, 3, 0),
+			Action: scheduled.ActionRemindCertificateProviderToComplete,
+		}).
+		Return(nil)
+
+	err := SignYourLpa(nil, donorStore, scheduledStore, testNowFn)(testAppData, w, r, &donordata.Provided{LpaID: "lpa-id", IdentityUserData: identity.UserData{Status: identity.StatusConfirmed}})
 	resp := w.Result()
 
 	assert.Nil(t, err)
@@ -113,7 +122,25 @@ func TestPostSignYourLpa(t *testing.T) {
 	assert.Equal(t, donor.PathWitnessingYourSignature.Format("lpa-id"), resp.Header.Get("Location"))
 }
 
-func TestPostSignYourLpaWhenStoreErrors(t *testing.T) {
+func TestPostSignYourLpaWhenScheduledStoreErrors(t *testing.T) {
+	form := url.Values{
+		"sign-lpa": {"want-to-sign", "want-to-apply"},
+	}
+
+	w := httptest.NewRecorder()
+	r, _ := http.NewRequest(http.MethodPost, "/", strings.NewReader(form.Encode()))
+	r.Header.Add("Content-Type", page.FormUrlEncoded)
+
+	scheduledStore := newMockScheduledStore(t)
+	scheduledStore.EXPECT().
+		Create(mock.Anything, mock.Anything).
+		Return(expectedError)
+
+	err := SignYourLpa(nil, nil, scheduledStore, testNowFn)(testAppData, w, r, &donordata.Provided{})
+	assert.ErrorIs(t, err, expectedError)
+}
+
+func TestPostSignYourLpaWhenDonorStoreErrors(t *testing.T) {
 	form := url.Values{
 		"sign-lpa": {"want-to-sign", "want-to-apply"},
 	}
@@ -122,13 +149,17 @@ func TestPostSignYourLpaWhenStoreErrors(t *testing.T) {
 	r, _ := http.NewRequest(http.MethodPost, "/", strings.NewReader(form.Encode()))
 	r.Header.Add("Content-Type", page.FormUrlEncoded)
 
+	scheduledStore := newMockScheduledStore(t)
+	scheduledStore.EXPECT().
+		Create(mock.Anything, mock.Anything).
+		Return(nil)
+
 	donorStore := newMockDonorStore(t)
 	donorStore.EXPECT().
 		Put(r.Context(), mock.Anything).
 		Return(expectedError)
 
-	err := SignYourLpa(nil, donorStore, testNowFn)(testAppData, w, r, &donordata.Provided{})
-
+	err := SignYourLpa(nil, donorStore, scheduledStore, testNowFn)(testAppData, w, r, &donordata.Provided{})
 	assert.Equal(t, expectedError, err)
 }
 
@@ -148,7 +179,7 @@ func TestPostSignYourLpaWhenValidationErrors(t *testing.T) {
 		})).
 		Return(nil)
 
-	err := SignYourLpa(template.Execute, nil, testNowFn)(testAppData, w, r, &donordata.Provided{})
+	err := SignYourLpa(template.Execute, nil, nil, testNowFn)(testAppData, w, r, &donordata.Provided{})
 	resp := w.Result()
 
 	assert.Nil(t, err)
diff --git a/internal/event/client.go b/internal/event/client.go
index 27325f5e96..754d673c0b 100644
--- a/internal/event/client.go
+++ b/internal/event/client.go
@@ -26,6 +26,7 @@ var events = map[any]string{
 	(*IdentityCheckMismatched)(nil):    "identity-check-mismatched",
 	(*CorrespondentUpdated)(nil):       "correspondent-updated",
 	(*LpaAccessGranted)(nil):           "lpa-access-granted",
+	(*LetterRequested)(nil):            "letter-requested",
 }
 
 type eventbridgeClient interface {
@@ -92,6 +93,10 @@ func (c *Client) SendLpaAccessGranted(ctx context.Context, event LpaAccessGrante
 	return send[LpaAccessGranted](ctx, c, event)
 }
 
+func (c *Client) SendLetterRequested(ctx context.Context, event LetterRequested) error {
+	return send[LetterRequested](ctx, c, event)
+}
+
 func send[T any](ctx context.Context, c *Client, detail any) error {
 	detailType, ok := events[(*T)(nil)]
 	if !ok {
diff --git a/internal/event/events.go b/internal/event/events.go
index 61d66d02b3..eb40e69e7b 100644
--- a/internal/event/events.go
+++ b/internal/event/events.go
@@ -106,3 +106,10 @@ type LpaAccessGrantedActor struct {
 	ActorUID  string `json:"actorUid"`
 	SubjectID string `json:"subjectId"`
 }
+
+type LetterRequested struct {
+	UID                   string        `json:"uid"`
+	LetterType            string        `json:"letterType"`
+	CorrespondentFullName string        `json:"correspondentFullName"`
+	CorrespondentAddress  place.Address `json:"correspondentAddress"`
+}
diff --git a/internal/notify/email.go b/internal/notify/email.go
index 318f7db5ed..7a64eaa5e7 100644
--- a/internal/notify/email.go
+++ b/internal/notify/email.go
@@ -404,3 +404,51 @@ func (e VoucherInformedTheyAreNoLongerNeededToVouchEmail) emailID(isProduction b
 
 	return "00ad14c6-f6df-4d7f-ae44-d7e27f6a9187"
 }
+
+type AdviseCertificateProviderToSignOrOptOutEmail struct {
+	DonorFullName               string
+	LpaType                     string
+	CertificateProviderFullName string
+	InvitedDate                 string
+	DeadlineDate                string
+}
+
+func (e AdviseCertificateProviderToSignOrOptOutEmail) emailID(isProduction bool, lang localize.Lang) string {
+	if isProduction {
+		if lang.IsCy() {
+			return "TODO"
+		}
+
+		return "TODO"
+	}
+
+	if lang.IsCy() {
+		return "22a19484-cd44-4476-a7b6-7826af5932ae"
+	}
+
+	return "d9b3e36a-5814-4e6b-84b1-baf763c49220"
+}
+
+type InformDonorCertificateProviderHasNotActedEmail struct {
+	CertificateProviderFullName string
+	LpaType                     string
+	DonorFullName               string
+	InvitedDate                 string
+	DeadlineDate                string
+}
+
+func (e InformDonorCertificateProviderHasNotActedEmail) emailID(isProduction bool, lang localize.Lang) string {
+	if isProduction {
+		if lang.IsCy() {
+			return "TODO"
+		}
+
+		return "TODO"
+	}
+
+	if lang.IsCy() {
+		return "4fc578f0-5cce-4082-a926-957aebb824bd"
+	}
+
+	return "0f7cbfed-1ffa-43d7-92c0-8d162aadc0ea"
+}
diff --git a/internal/scheduled/action.go b/internal/scheduled/action.go
index b58f0c1f98..1171dc6560 100644
--- a/internal/scheduled/action.go
+++ b/internal/scheduled/action.go
@@ -1,5 +1,7 @@
 package scheduled
 
+import "time"
+
 //go:generate enumerator -type Action -trimprefix
 type Action uint8
 
@@ -8,4 +10,39 @@ const (
 	// their LPA, and if so remove their identity data and notify them of the
 	// change.
 	ActionExpireDonorIdentity Action = iota + 1
+
+	// ActionRemindCertificateProviderToComplete will check that the target
+	// certificate provider has neither provided the certificate nor opted-out,
+	// and if so send them a reminder email or letter, plus another to the donor
+	// (or correspondent, if set).
+	ActionRemindCertificateProviderToComplete
+
+	// ActionRemindCertificateProviderToConfirmIdentity will check that the target
+	// certificate provider has not confirmed their identity, and if so send them
+	// a reminder email or letter, plus another to the donor (or correspondent, if
+	// set).
+	ActionRemindCertificateProviderToConfirmIdentity
 )
+
+// ExpireDonorIdentityAt gives the time to run ActionExpireDonorIdentity, which
+// is 6 months after the donor has checked the LPA.
+func ExpireDonorIdentityAt(donorCheckedAt time.Time) time.Time {
+	return donorCheckedAt.AddDate(0, 6, 0)
+}
+
+// RemindCertificateProviderAt gives the time to run
+// ActionRemindCertificateProviderToConfirmIdentity and
+// ActionRemindCertificateProviderToComplete, which is the latest of
+//
+//	3 months after the certificate provider invite is sent
+//	3 months until the LPA expires
+func RemindCertificateProviderAt(inviteSentAt, donorSignedAt time.Time) time.Time {
+	afterInvite := inviteSentAt.AddDate(0, 3, 0)
+	beforeExpiry := donorSignedAt.AddDate(0, 21, 0)
+
+	if afterInvite.After(beforeExpiry) {
+		return afterInvite
+	}
+
+	return beforeExpiry
+}
diff --git a/internal/scheduled/mock_Bundle_test.go b/internal/scheduled/mock_Bundle_test.go
new file mode 100644
index 0000000000..4c2c4a80f7
--- /dev/null
+++ b/internal/scheduled/mock_Bundle_test.go
@@ -0,0 +1,83 @@
+// Code generated by mockery. DO NOT EDIT.
+
+package scheduled
+
+import (
+	localize "github.com/ministryofjustice/opg-modernising-lpa/internal/localize"
+	mock "github.com/stretchr/testify/mock"
+)
+
+// mockBundle is an autogenerated mock type for the Bundle type
+type mockBundle struct {
+	mock.Mock
+}
+
+type mockBundle_Expecter struct {
+	mock *mock.Mock
+}
+
+func (_m *mockBundle) EXPECT() *mockBundle_Expecter {
+	return &mockBundle_Expecter{mock: &_m.Mock}
+}
+
+// For provides a mock function with given fields: lang
+func (_m *mockBundle) For(lang localize.Lang) *localize.Localizer {
+	ret := _m.Called(lang)
+
+	if len(ret) == 0 {
+		panic("no return value specified for For")
+	}
+
+	var r0 *localize.Localizer
+	if rf, ok := ret.Get(0).(func(localize.Lang) *localize.Localizer); ok {
+		r0 = rf(lang)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*localize.Localizer)
+		}
+	}
+
+	return r0
+}
+
+// mockBundle_For_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'For'
+type mockBundle_For_Call struct {
+	*mock.Call
+}
+
+// For is a helper method to define mock.On call
+//   - lang localize.Lang
+func (_e *mockBundle_Expecter) For(lang interface{}) *mockBundle_For_Call {
+	return &mockBundle_For_Call{Call: _e.mock.On("For", lang)}
+}
+
+func (_c *mockBundle_For_Call) Run(run func(lang localize.Lang)) *mockBundle_For_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run(args[0].(localize.Lang))
+	})
+	return _c
+}
+
+func (_c *mockBundle_For_Call) Return(_a0 *localize.Localizer) *mockBundle_For_Call {
+	_c.Call.Return(_a0)
+	return _c
+}
+
+func (_c *mockBundle_For_Call) RunAndReturn(run func(localize.Lang) *localize.Localizer) *mockBundle_For_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// newMockBundle creates a new instance of mockBundle. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.
+// The first argument is typically a *testing.T value.
+func newMockBundle(t interface {
+	mock.TestingT
+	Cleanup(func())
+}) *mockBundle {
+	mock := &mockBundle{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}
diff --git a/internal/scheduled/mock_CertificateProviderStore_test.go b/internal/scheduled/mock_CertificateProviderStore_test.go
new file mode 100644
index 0000000000..458d06840e
--- /dev/null
+++ b/internal/scheduled/mock_CertificateProviderStore_test.go
@@ -0,0 +1,99 @@
+// Code generated by mockery. DO NOT EDIT.
+
+package scheduled
+
+import (
+	context "context"
+
+	certificateproviderdata "github.com/ministryofjustice/opg-modernising-lpa/internal/certificateprovider/certificateproviderdata"
+
+	dynamo "github.com/ministryofjustice/opg-modernising-lpa/internal/dynamo"
+
+	mock "github.com/stretchr/testify/mock"
+)
+
+// mockCertificateProviderStore is an autogenerated mock type for the CertificateProviderStore type
+type mockCertificateProviderStore struct {
+	mock.Mock
+}
+
+type mockCertificateProviderStore_Expecter struct {
+	mock *mock.Mock
+}
+
+func (_m *mockCertificateProviderStore) EXPECT() *mockCertificateProviderStore_Expecter {
+	return &mockCertificateProviderStore_Expecter{mock: &_m.Mock}
+}
+
+// One provides a mock function with given fields: ctx, pk
+func (_m *mockCertificateProviderStore) One(ctx context.Context, pk dynamo.LpaKeyType) (*certificateproviderdata.Provided, error) {
+	ret := _m.Called(ctx, pk)
+
+	if len(ret) == 0 {
+		panic("no return value specified for One")
+	}
+
+	var r0 *certificateproviderdata.Provided
+	var r1 error
+	if rf, ok := ret.Get(0).(func(context.Context, dynamo.LpaKeyType) (*certificateproviderdata.Provided, error)); ok {
+		return rf(ctx, pk)
+	}
+	if rf, ok := ret.Get(0).(func(context.Context, dynamo.LpaKeyType) *certificateproviderdata.Provided); ok {
+		r0 = rf(ctx, pk)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*certificateproviderdata.Provided)
+		}
+	}
+
+	if rf, ok := ret.Get(1).(func(context.Context, dynamo.LpaKeyType) error); ok {
+		r1 = rf(ctx, pk)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// mockCertificateProviderStore_One_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'One'
+type mockCertificateProviderStore_One_Call struct {
+	*mock.Call
+}
+
+// One is a helper method to define mock.On call
+//   - ctx context.Context
+//   - pk dynamo.LpaKeyType
+func (_e *mockCertificateProviderStore_Expecter) One(ctx interface{}, pk interface{}) *mockCertificateProviderStore_One_Call {
+	return &mockCertificateProviderStore_One_Call{Call: _e.mock.On("One", ctx, pk)}
+}
+
+func (_c *mockCertificateProviderStore_One_Call) Run(run func(ctx context.Context, pk dynamo.LpaKeyType)) *mockCertificateProviderStore_One_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run(args[0].(context.Context), args[1].(dynamo.LpaKeyType))
+	})
+	return _c
+}
+
+func (_c *mockCertificateProviderStore_One_Call) Return(_a0 *certificateproviderdata.Provided, _a1 error) *mockCertificateProviderStore_One_Call {
+	_c.Call.Return(_a0, _a1)
+	return _c
+}
+
+func (_c *mockCertificateProviderStore_One_Call) RunAndReturn(run func(context.Context, dynamo.LpaKeyType) (*certificateproviderdata.Provided, error)) *mockCertificateProviderStore_One_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// newMockCertificateProviderStore creates a new instance of mockCertificateProviderStore. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.
+// The first argument is typically a *testing.T value.
+func newMockCertificateProviderStore(t interface {
+	mock.TestingT
+	Cleanup(func())
+}) *mockCertificateProviderStore {
+	mock := &mockCertificateProviderStore{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}
diff --git a/internal/scheduled/mock_EventClient_test.go b/internal/scheduled/mock_EventClient_test.go
new file mode 100644
index 0000000000..b619d8c578
--- /dev/null
+++ b/internal/scheduled/mock_EventClient_test.go
@@ -0,0 +1,84 @@
+// Code generated by mockery. DO NOT EDIT.
+
+package scheduled
+
+import (
+	context "context"
+
+	event "github.com/ministryofjustice/opg-modernising-lpa/internal/event"
+	mock "github.com/stretchr/testify/mock"
+)
+
+// mockEventClient is an autogenerated mock type for the EventClient type
+type mockEventClient struct {
+	mock.Mock
+}
+
+type mockEventClient_Expecter struct {
+	mock *mock.Mock
+}
+
+func (_m *mockEventClient) EXPECT() *mockEventClient_Expecter {
+	return &mockEventClient_Expecter{mock: &_m.Mock}
+}
+
+// SendLetterRequested provides a mock function with given fields: ctx, _a1
+func (_m *mockEventClient) SendLetterRequested(ctx context.Context, _a1 event.LetterRequested) error {
+	ret := _m.Called(ctx, _a1)
+
+	if len(ret) == 0 {
+		panic("no return value specified for SendLetterRequested")
+	}
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(context.Context, event.LetterRequested) error); ok {
+		r0 = rf(ctx, _a1)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
+// mockEventClient_SendLetterRequested_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'SendLetterRequested'
+type mockEventClient_SendLetterRequested_Call struct {
+	*mock.Call
+}
+
+// SendLetterRequested is a helper method to define mock.On call
+//   - ctx context.Context
+//   - _a1 event.LetterRequested
+func (_e *mockEventClient_Expecter) SendLetterRequested(ctx interface{}, _a1 interface{}) *mockEventClient_SendLetterRequested_Call {
+	return &mockEventClient_SendLetterRequested_Call{Call: _e.mock.On("SendLetterRequested", ctx, _a1)}
+}
+
+func (_c *mockEventClient_SendLetterRequested_Call) Run(run func(ctx context.Context, _a1 event.LetterRequested)) *mockEventClient_SendLetterRequested_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run(args[0].(context.Context), args[1].(event.LetterRequested))
+	})
+	return _c
+}
+
+func (_c *mockEventClient_SendLetterRequested_Call) Return(_a0 error) *mockEventClient_SendLetterRequested_Call {
+	_c.Call.Return(_a0)
+	return _c
+}
+
+func (_c *mockEventClient_SendLetterRequested_Call) RunAndReturn(run func(context.Context, event.LetterRequested) error) *mockEventClient_SendLetterRequested_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// newMockEventClient creates a new instance of mockEventClient. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.
+// The first argument is typically a *testing.T value.
+func newMockEventClient(t interface {
+	mock.TestingT
+	Cleanup(func())
+}) *mockEventClient {
+	mock := &mockEventClient{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}
diff --git a/internal/scheduled/runner.go b/internal/scheduled/runner.go
index 748a756173..0560ec4220 100644
--- a/internal/scheduled/runner.go
+++ b/internal/scheduled/runner.go
@@ -10,9 +10,12 @@ import (
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/service/cloudwatch"
 	"github.com/aws/aws-sdk-go-v2/service/cloudwatch/types"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/certificateprovider/certificateproviderdata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor/donordata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/dynamo"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/event"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/identity"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/localize"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/lpastore/lpadata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/task"
@@ -32,6 +35,10 @@ type DonorStore interface {
 	Put(ctx context.Context, provided *donordata.Provided) error
 }
 
+type CertificateProviderStore interface {
+	One(ctx context.Context, pk dynamo.LpaKeyType) (*certificateproviderdata.Provided, error)
+}
+
 type NotifyClient interface {
 	SendActorEmail(ctx context.Context, to notify.ToEmail, lpaUID string, email notify.Email) error
 }
@@ -54,34 +61,47 @@ type LpaStoreClient interface {
 	Lpa(ctx context.Context, lpaUID string) (*lpadata.Lpa, error)
 }
 
+type Bundle interface {
+	For(lang localize.Lang) *localize.Localizer
+}
+
+type EventClient interface {
+	SendLetterRequested(ctx context.Context, event event.LetterRequested) error
+}
+
 type Runner struct {
-	logger        Logger
-	store         ScheduledStore
-	now           func() time.Time
-	since         func(time.Time) time.Duration
-	donorStore    DonorStore
-	notifyClient  NotifyClient
-	actions       map[Action]ActionFunc
-	waiter        Waiter
-	metricsClient MetricsClient
-	processed     float64
-	ignored       float64
-	errored       float64
+	logger                   Logger
+	store                    ScheduledStore
+	now                      func() time.Time
+	since                    func(time.Time) time.Duration
+	donorStore               DonorStore
+	certificateProviderStore CertificateProviderStore
+	notifyClient             NotifyClient
+	eventClient              EventClient
+	bundle                   Bundle
+	actions                  map[Action]ActionFunc
+	waiter                   Waiter
+	metricsClient            MetricsClient
+	processed                float64
+	ignored                  float64
+	errored                  float64
 	// TODO remove in MLPAB-2690
 	metricsEnabled bool
 }
 
-func NewRunner(logger Logger, store ScheduledStore, donorStore DonorStore, notifyClient NotifyClient, metricsClient MetricsClient, metricsEnabled bool) *Runner {
+func NewRunner(logger Logger, store ScheduledStore, donorStore DonorStore, certificateProviderStore CertificateProviderStore, notifyClient NotifyClient, bundle Bundle, metricsClient MetricsClient, metricsEnabled bool) *Runner {
 	r := &Runner{
-		logger:         logger,
-		store:          store,
-		now:            time.Now,
-		since:          time.Since,
-		donorStore:     donorStore,
-		notifyClient:   notifyClient,
-		waiter:         &waiter{backoff: time.Second, sleep: time.Sleep, maxRetries: 10},
-		metricsClient:  metricsClient,
-		metricsEnabled: metricsEnabled,
+		logger:                   logger,
+		store:                    store,
+		now:                      time.Now,
+		since:                    time.Since,
+		donorStore:               donorStore,
+		certificateProviderStore: certificateProviderStore,
+		notifyClient:             notifyClient,
+		bundle:                   bundle,
+		waiter:                   &waiter{backoff: time.Second, sleep: time.Sleep, maxRetries: 10},
+		metricsClient:            metricsClient,
+		metricsEnabled:           metricsEnabled,
 	}
 
 	r.actions = map[Action]ActionFunc{
@@ -220,3 +240,91 @@ func (r *Runner) stepCancelDonorIdentity(ctx context.Context, row *Event) error
 
 	return nil
 }
+
+func (r *Runner) stepRemindCertificateProviderToComplete(ctx context.Context, row *Event) error {
+	certificateProvider, err := r.certificateProviderStore.One(ctx, row.TargetLpaKey)
+	if err != nil && !errors.Is(err, dynamo.NotFoundError{}) {
+		return fmt.Errorf("error retrieving certificate provider: %w", err)
+	}
+
+	if certificateProvider != nil && certificateProvider.Tasks.ProvideTheCertificate.IsCompleted() {
+		return errStepIgnored
+	}
+
+	provided, err := r.donorStore.One(ctx, row.TargetLpaKey, row.TargetLpaOwnerKey)
+	if err != nil {
+		return fmt.Errorf("error retrieving donor: %w", err)
+	}
+
+	beforeExpiry := provided.ExpiresAt().AddDate(0, -3, 0)
+	afterInvite := provided.CertificateProviderInvitedAt.AddDate(0, 3, 0)
+
+	if r.now().Before(afterInvite) || r.now().Before(beforeExpiry) {
+		return errStepIgnored
+	}
+
+	emailTo := notify.ToCertificateProvider(provided.CertificateProvider)
+	if certificateProvider != nil {
+		emailTo = notify.ToProvidedCertificateProvider(certificateProvider, provided.CertificateProvider)
+	}
+
+	if provided.CertificateProvider.CarryOutBy.IsPaper() {
+		if err := r.eventClient.SendLetterRequested(ctx, event.LetterRequested{
+			UID:                   provided.LpaUID,
+			LetterType:            "ADVISE_CERTIFICATE_PROVIDER_TO_SIGN_OR_OPT_OUT",
+			CorrespondentFullName: provided.CertificateProvider.FullName(),
+			CorrespondentAddress:  provided.CertificateProvider.Address,
+		}); err != nil {
+			return fmt.Errorf("could not send certificate provider letter request: %w", err)
+		}
+	} else {
+		var localizer *localize.Localizer
+		if certificateProvider != nil && !certificateProvider.ContactLanguagePreference.Empty() {
+			localizer = r.bundle.For(certificateProvider.ContactLanguagePreference)
+		} else {
+			localizer = r.bundle.For(localize.En)
+		}
+
+		if err := r.notifyClient.SendActorEmail(ctx, emailTo, provided.LpaUID, notify.AdviseCertificateProviderToSignOrOptOutEmail{
+			DonorFullName:               provided.Donor.FullName(),
+			LpaType:                     localizer.T(provided.Type.String()),
+			CertificateProviderFullName: provided.CertificateProvider.FullName(),
+			InvitedDate:                 localizer.FormatDate(provided.CertificateProviderInvitedAt),
+			DeadlineDate:                localizer.FormatDate(provided.ExpiresAt()),
+		}); err != nil {
+			return fmt.Errorf("could not send certificate provider email: %w", err)
+		}
+	}
+
+	if provided.Donor.Channel.IsPaper() {
+		letterRequest := event.LetterRequested{
+			UID:                   provided.LpaUID,
+			LetterType:            "INFORM_DONOR_CERTIFICATE_PROVIDER_HAS_NOT_ACTED",
+			CorrespondentFullName: provided.Donor.FullName(),
+			CorrespondentAddress:  provided.Donor.Address,
+		}
+
+		if provided.Correspondent.Address.Line1 != "" {
+			letterRequest.CorrespondentFullName = provided.Correspondent.FullName()
+			letterRequest.CorrespondentAddress = provided.Correspondent.Address
+		}
+
+		if err := r.eventClient.SendLetterRequested(ctx, letterRequest); err != nil {
+			return fmt.Errorf("could not send certificate provider letter request: %w", err)
+		}
+	} else {
+		localizer := r.bundle.For(provided.Donor.ContactLanguagePreference)
+
+		if err := r.notifyClient.SendActorEmail(ctx, notify.ToDonor(provided), provided.LpaUID, notify.InformDonorCertificateProviderHasNotActedEmail{
+			CertificateProviderFullName: provided.CertificateProvider.FullName(),
+			LpaType:                     localizer.T(provided.Type.String()),
+			DonorFullName:               provided.Donor.FullName(),
+			InvitedDate:                 localizer.FormatDate(provided.CertificateProviderInvitedAt),
+			DeadlineDate:                localizer.FormatDate(provided.ExpiresAt()),
+		}); err != nil {
+			return fmt.Errorf("could not send donor email: %w", err)
+		}
+	}
+
+	return nil
+}
diff --git a/internal/scheduled/runner_test.go b/internal/scheduled/runner_test.go
index 017fb629c7..2f46406d8e 100644
--- a/internal/scheduled/runner_test.go
+++ b/internal/scheduled/runner_test.go
@@ -54,10 +54,12 @@ func TestNewRunner(t *testing.T) {
 	logger := newMockLogger(t)
 	store := newMockScheduledStore(t)
 	donorStore := newMockDonorStore(t)
+	certificateProviderStore := newMockCertificateProviderStore(t)
 	notifyClient := newMockNotifyClient(t)
 	metricsClient := newMockMetricsClient(t)
+	bundle := newMockBundle(t)
 
-	runner := NewRunner(logger, store, donorStore, notifyClient, metricsClient, true)
+	runner := NewRunner(logger, store, donorStore, certificateProviderStore, notifyClient, bundle, metricsClient, true)
 
 	assert.Equal(t, logger, runner.logger)
 	assert.Equal(t, store, runner.store)