The National Co-operative Archive, located in Manchester, UK, is home to collections relating to the history of the co-operative movement, that provide an unrivaled resource for the understanding of co-operative movement from its initial ideas of the nineteenth century to the present day. The archive includes manuscripts, rare books, periodicals, films, photographs and oral histories, and was effectively founded in 1903.

More information on the Wikipedia page [1]

The website is [2]