diff --git a/src/grib_expression_class_is_in_list.cc b/src/grib_expression_class_is_in_list.cc
index 4a6c3dc3b..0d61cf82c 100644
--- a/src/grib_expression_class_is_in_list.cc
+++ b/src/grib_expression_class_is_in_list.cc
@@ -173,22 +173,23 @@ static int evaluate_long(grib_expression* g, grib_handle* h, long* result)
 
 static int evaluate_double(grib_expression* g, grib_handle* h, double* result)
 {
-    grib_expression_is_in_list* e = (grib_expression_is_in_list*)g;
-    int err                       = 0;
-    char mybuf[1024]              = {0,};
-    size_t size = 1024;
+    return GRIB_NOT_IMPLEMENTED;
+    // grib_expression_is_in_list* e = (grib_expression_is_in_list*)g;
+    // int err                       = 0;
+    // char mybuf[1024]              = {0,};
+    // size_t size = 1024;
 
-    grib_trie* list = load_list(h->context, g, &err);
+    // grib_trie* list = load_list(h->context, g, &err);
 
-    if ((err = grib_get_string_internal(h, e->name, mybuf, &size)) != GRIB_SUCCESS)
-        return err;
+    // if ((err = grib_get_string_internal(h, e->name, mybuf, &size)) != GRIB_SUCCESS)
+    //     return err;
 
-    if (grib_trie_get(list, mybuf))
-        *result = 1;
-    else
-        *result = 0;
+    // if (grib_trie_get(list, mybuf))
+    //     *result = 1;
+    // else
+    //     *result = 0;
 
-    return err;
+    // return err;
 }
 
 static string evaluate_string(grib_expression* g, grib_handle* h, char* buf, size_t* size, int* err)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3bed4fc84..9c50bad59 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -97,6 +97,7 @@ if( HAVE_BUILD_TOOLS )
         grib_ifsParam
         grib_packing_order
         filter_substr
+        filter_is_in_list
         filter_transient_darray
         grib_uerra
         grib_ecpoint
diff --git a/tests/filter_is_in_list.sh b/tests/filter_is_in_list.sh
new file mode 100755
index 000000000..4f771a43b
--- /dev/null
+++ b/tests/filter_is_in_list.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+# (C) Copyright 2005- ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# 
+# In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
+# virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
+#
+
+. ./include.ctest.sh
+
+label="filter_is_in_list_test"
+temp=temp.$label.txt
+sample=$ECCODES_SAMPLES_PATH/GRIB2.tmpl
+
+# Evaluate long
+${tools_dir}/grib_filter - $sample <<EOF
+  transient a_name="#";
+  if (is_in_list(a_name, "boot.def")) {
+    print "Found";
+  }
+EOF
+
+# Evaluate string
+${tools_dir}/grib_filter - $sample <<EOF
+  transient a_name="#";
+  transient the_cond = (is_in_list(a_name, "boot.def"));
+  if (the_cond) {
+    print "Found";
+  }
+EOF
+
+# Illegal cases
+${tools_dir}/grib_filter - $sample 2>$temp <<EOF
+  transient a_name="xyz";
+  if (is_in_list(a_name, "existential nihilism")) {
+    print "Found";
+  }
+EOF
+grep -q "unable to find def file" $temp
+
+
+# Clean up
+rm -f $temp