diff --git a/R/internals_RLum.R b/R/internals_RLum.R
index a5501f520..d2cecb584 100644
--- a/R/internals_RLum.R
+++ b/R/internals_RLum.R
@@ -1335,6 +1335,28 @@ SW <- function(expr) {
   }
 }
 
+#' @title Validate logical scalar variables
+#'
+#' @param val [numeric] (**required**): value to validate
+#' @param null.ok [logical] (*with default*): whether a `NULL` value should be
+#'        considered valid (`FALSE` by default)
+#' @param name [character] (*with default*): variable name to report in case
+#'        of error: if specified, it's reported as is; if not specified it's
+#'        inferred from the name of the variable tested and reported with
+#'        quotes.
+#'
+#' @md
+#' @noRd
+.validate_logical_scalar <- function(val, null.ok = FALSE, name = NULL) {
+  if (missing(val) || is.null(val) && null.ok)
+    return()
+  if (!is.logical(val) || length(val) != 1 || is.na(val)) {
+    if (is.null(name))
+      name <- sprintf("'%s'", all.vars(match.call())[1])
+    .throw_error(name, " should be a single logical value")
+  }
+}
+
 #' Check that a suggested package is installed
 #'
 #' Report a message with installation instructions if a suggested package
diff --git a/tests/testthat/test_internals.R b/tests/testthat/test_internals.R
index 8fafe1553..7205c20f9 100644
--- a/tests/testthat/test_internals.R
+++ b/tests/testthat/test_internals.R
@@ -380,6 +380,25 @@ test_that("Test internals", {
   expect_error(.validate_positive_scalar(NA, int = TRUE, name = "The variable"),
                "The variable should be a positive integer")
 
+  ## .validate_logical_scalar() ---------------------------------------------
+  expect_silent(.validate_logical_scalar())
+  expect_silent(.validate_logical_scalar(TRUE))
+  expect_silent(.validate_logical_scalar(FALSE))
+  expect_silent(.validate_logical_scalar(NULL, null.ok = TRUE))
+
+  expect_error(.validate_logical_scalar(test <- "a"),
+               "'test' should be a single logical value")
+  expect_error(.validate_logical_scalar(test <- NULL),
+               "'test' should be a single logical value")
+  expect_error(.validate_logical_scalar(iris),
+               "'iris' should be a single logical value")
+  expect_error(.validate_logical_scalar(c(TRUE, FALSE), name = "'var'"),
+               "'var' should be a single logical value")
+  expect_error(.validate_logical_scalar(0, name = "'var'"),
+               "'var' should be a single logical value")
+  expect_error(.validate_logical_scalar(NA, name = "The variable"),
+               "The variable should be a single logical value")
+
   ## .require_suggested_package() -------------------------------------------
   expect_true(.require_suggested_package("utils"))
   expect_error(.require_suggested_package("error"),