The seat had become vacant on 14 November 1938, when the constituency's National Liberal Member of Parliament (MP), William Lygon, Viscount Elmley had succeeded to the peerage as the 8th Earl Beauchamp.
He joined the breakaway National Liberals in 1931, and at the following General election was not opposed by the Conservatives.
Only two candidates contested the by-election: Frank Medlicott for the National Liberals, and Norman Tillett for the Labour Party.
Medlicott was a 36-year-old London solicitor who had not contested an election since standing for the Liberal Party at Acton in 1929.
For a while, it seemed as if James F. Wright, the secretary of the Norfolk National Farmers' Union and former leader of the Agricultural Party, would run as an Independent Conservative, but by close of nominations, there were just the two candidates.