The founders of the organisation were Charles Kimber, Derek Rawnsley and Patrick Ransome. Other noted members of Federal Union included Harold Wilson, Barbara Wootton, C. E. M. Joad, Stephen King-Hall and Philip Kerr, 11th Marquess of Lothian. In 1940 the group set up a Federal Union Research Institute (FURI), chaired by William Beveridge, to discuss the direction of post-war European integration. FURI attracted contributors from across the political spectrum, including F.A. Hayek, J. B. Priestley, H. N. Brailsford, Lionel Robbins and Arnold Toynbee. 
The organisation argues that federalism is the division of political power between levels of government to achieve the best combination of democracy and effectiveness, and does not necessarily involve the bureaucratic centralisation of common assumption.
Federal Union believes that democracy and the rule of law should apply between states as well as within them. Federal Union is also the British section of the Union of European Federalists and of the World Federalist Movement.
- Obituary:Sir Charles Kimber Daily Telegraph, 22 April 2008. Retrieved 20 January 2013.
- Peter Barberis, John McHugh, Mike Tyldesley, Encyclopedia of British and Irish Political Organizations: Parties, Groups and Movements of the 20th Century, Continuum International Publishing Group, 2000, ISBN 0826458149. (p.135)
- Michael Burgess, The British Tradition of Federalism. Fairleigh Dickinson Univ Press, 1995. ISBN 0838636187 (p.142)