diff --git a/src/sirius_interface.F b/src/sirius_interface.F
index 1f6acc458b..9a306002d7 100644
--- a/src/sirius_interface.F
+++ b/src/sirius_interface.F
@@ -985,6 +985,14 @@ CONTAINS
    SUBROUTINE cp_sirius_init()
    END SUBROUTINE cp_sirius_init
 
+! **************************************************************************************************
+!> \brief Return always .FALSE. because the Sirius library is not compiled in.
+!> \return Return the initialisation status of the Sirius library as boolean
+! **************************************************************************************************
+   LOGICAL FUNCTION cp_sirius_is_initialized()
+      cp_sirius_is_initialized = .FALSE.
+   END FUNCTION cp_sirius_is_initialized
+
 ! **************************************************************************************************
 !> \brief Empty implementation in case SIRIUS is not compiled in.
 ! **************************************************************************************************