Namespaced URLs are specified using the : operator. For example, the main index page of the admin application is referenced using admin:index. This indicates a namespace of admin, and a named URL of index.
url(r'^admin/', include(admin.site.urls)),
[1] https://docs.djangoproject.com/en/dev/topics/http/urls/#url-namespaces [2] https://docs.djangoproject.com/en/1.3/intro/tutorial02/
-- Alasdair Nicol Developer, MEMSET mail: alas...@memset.com web: http://www.memset.com/ Memset Ltd., registration number 4504980. 25 Frederick Sanger Road, Guildford, Surrey, GU2 7YD, UK.
Try:
{% url admin:index %}
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#reversing-admin-urls