The by-election was caused by the death of the sitting Conservative MP, Frank Heilgers who was killed in the Ilford rail crash on 16 January 1944.

[2] He had been a member of West Suffolk County Council since 1933, and was selected in 1938 as the Conservative prospective parliamentary candidate for the Isle of Ely constituency,[1] to stand against Liberal MP James de Rothschild.

The Bury St Edmunds Liberals had selected H.C. Drayton as prospective parliamentary candidate for the next general election.

Ashby had a track record of flying the Liberal flag in some less hopeful constituencies that included 1918 Birmingham Ladywood, 1922 and 1923 Richmond, Surrey, 1924 Watford, 1929 Hendon and 1935 and 1937 Hemel Hempstead.

Secondly, she was able to enlist the support of Richard Acland and his successful Common Wealth Party by-election circus.

This group included Liberal, Labour and Communist activists, harking back to the pre-war days of the Popular Front.