The Co-operative Party is the political arm of the British Co-operative Movement, and all its members must also be members of a bona fide Co-operative Society.
For the first seventy years of its history the Co-operative Movement adopted a stance of political neutrality, but during the First World War and the consequent introduction of rationing and conscription, co-operatives felt they were being unfairly penalised by the government. As a result a special congress of the movement resolved to establish a Co-operative Representation Committee. Candidates were put forward in the 1918 Khaki election and one member of parliament was elected.
From the beginning Co-operative MPs accepted the Labour whip in Parliament an arrangement that was formalised through an electoral agreement signed in 1927 that has remained in place ever since.
Candidates are styled as 'Labour and Co-operative' and, aside from a commitment to specifically supporting co-operatives and the social economy, are to all intents and purposes indistinguishable from plain vanilla Labour. In fact, it is probably fair to say that most voters in the Britain have no idea that such a creature as the Co-operative Party exists.
The party currently has 29 MPs at Westminster, 7 Scottish MSPs, 5 Welsh Assembly members and around 700 local councillors all elected on the joint 'Labour and Co-operative' ticket.