The Conservative candidate was Maurice Roche, who had been the MP for King's Lynn from 1924 until he stepped down in favour of Maxwell at the 1935 general election. Although a hereditary peer, his succession in 1920 to the title of Baron Fermoy had not disqualified him from the House of Commons, because his title was in the Peerage of Ireland, and did not grant a seat in the House of Lords.
During World War II, the parties in the Coalition Government had agreed not to contest by-elections in seats held by other coalition parties, and many wartime by-elections were therefore unopposed. However, local party members who disagreed with the truce could not be prevented from standing as independent candidates. In King's Lynn, Frederick Wise, who had been the official Labour Party candidate at the 1935 general election, stood as an "Independent Labour" candidate.
Result
On a heavily reduced turnout, Lord Fermoy held the seat for the Conservatives, albeit with a much reduced majority. Fermoy retired (for a second time) at the 1945 general election, when Wise won the seat as an official Labour Party candidate.
Craig, F. W. S. (1983) [1969]. British parliamentary election results 1918-1949 (3rd ed.). Chichester: Parliamentary Research Services. ISBN0-900178-06-X.