diff --git a/src/calibre/spell/dictionary.py b/src/calibre/spell/dictionary.py
index ca26dae298..5315c180e9 100644
--- a/src/calibre/spell/dictionary.py
+++ b/src/calibre/spell/dictionary.py
@@ -436,7 +436,7 @@ def find_tests():
         def setUp(self):
             dictionaries = Dictionaries()
             dictionaries.initialize()
-            eng = parse_lang_code('en')
+            eng = parse_lang_code('en-GB')
             self.recognized = partial(dictionaries.recognized, locale=eng)
             self.suggestions = partial(dictionaries.suggestions, locale=eng)