diff --git a/wye/organisations/views.py b/wye/organisations/views.py
index 8952c14..0900c4e 100644
--- a/wye/organisations/views.py
+++ b/wye/organisations/views.py
@@ -176,7 +176,7 @@ def get_token(self, user, **kwargs):
 
     def get_urls(self):
         return patterns('',
-                        url(r'^(?P<user_id>[\d]+)-(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/',
+                        url(r'^(?P<user_id>[0-9]+)-(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/',
                             view=self.activate_view, name="invitation_register")
                         )
 
diff --git a/wye/urls.py b/wye/urls.py
index 19ec741..14e2d66 100644
--- a/wye/urls.py
+++ b/wye/urls.py
@@ -43,7 +43,7 @@
         include('wye.regions.urls', namespace="regions")),
     url(r'^reports/',
         include('wye.reports.urls', namespace="reports")),
-    url(r'^invitation/(?P<user_id>[\d]+)-(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/',
+    url(r'^invitation/(?P<user_id>[0-9]+)-(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/',
         view=activate_view, name="invitation_register"),
     url(r'^$', HomePageView.as_view(),
         name='home-page'),