Defra wiki

defra wiki was set-up by the 'Department for , Food and Rural Affairs' (defra) – a  ministry department of the  of Great Britain and Northern Ireland. It was aimed at developing the idea of an Environmental Contract.

It was experiment in colaborative, community-based public policy, but was halted soon after it started because of large amounts of vandalism. See Sky News article: Web Policy Goes Wrong.
 * News
 * "A Government minister's attempt to get web users to help form policy has backfired .... Administrators were forced to withdraw the page after it was defaced by more than 170 people over a frenzied few hours."

The wiki was set up with the  wiki engine, but is now , presumably after JotSpot was aquired by Google. The Internet Archive WaybackMachine created 56 captures of the site from 09 September 2006, the last being 05 December 2008.