At a national level, the relationship that existed between the Liberal and Labour parties from 1906 to 1918 was referred to as the Progressive Alliance.
Dr Billy Carritt, a member of the Communist party, fought the 1939 Westminster Abbey by-election.
With a general election expected to take place in the autumn of 1939, in a number of constituencies, the local Labour and Liberal parties agreed not to run their own candidates but instead adopt an Independent Progressive.
In addition to Vernon Bartlett (Bridgwater), there was Patrick Early (Banbury), William John Brown (Stroud), William Robert Robins, (Cirencester and Tewkesbury), Michael Alexander Pinney (Tiverton) and John Langdon-Davies, (Rye).
During the war, this trend continued with Prof. John Alfred Ryle, who fought the 1940 Cambridge University by-election.