The Union of Shop, Distributive and Allied Workers or USDAW is the British Trades Union representing workers in the retail trade. It was creates on the 1st January 1947 by the merger of the National Union of Distributive and Allied Workers and the National Amalgamated Union of Shop Assistants, Warehousemen and Clerks.
The Union now has over 310,000 members and has seen steady growth since formation due to both the growth in the retail sector as well as the shift from smaller to larger retailers (Which oddly enough, unions prefer as it makes it easier to recruit and organise.