Labour Party
Britain's "democratic socialist party". Currently led by centrist Prime Minister Tony Blair, who is the chief advocate of the "Third Way" philosophy. Includes policies, announcements and membership information.

labour-party.org.uk
Unofficial site with text of Labour manifestoes from 1945 onwards and a directory of Labour Party links.

The Co-operative Party
The political arm of the British Co-operative Movement, affiliated with and runs candidates jointly with Labour. Policies, publications and details of its role in the Commons and Lords.

The Virtual & Global Social Democratic Party (VirGlob-SP)
The first worldwide political education project to communicate only online. It aims to promote the direct political exchange between the social and democratic grass-roots activists throughout the world.

Wikipedia - Labour Party (UK)
Hyperlinked encyclopedia entry offers the history, leaders and structure of the party. Includes lists of organizations and members.