The seat had become vacant when the Conservative Member of Parliament (MP) Somerset Maxwell had died in December 1942 from wounds received at the Battle of El Alamein.
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.
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.
Fermoy retired (for a second time) at the 1945 general election, when Wise won the seat as an official Labour Party candidate.