Preston by election, 1940

The Preston by-election, 1940 was a parliamentary by-election held for the British House of Commons constituency of Preston in Lancashire on 29 September 1940. The seat had become vacant on the death of the Conservative Member of Parliament Adrian Moreing, who had held the seat since the 1931 general election.

During World War II, the parties in the war-time coalition government had agreed not contest by-elections where a seat held by any of their parties fell vacant, so the Conservative candidate, Randolph Churchill (son of Prime Minister Winston Churchill), was returned unopposed. He represented the constituency until his defeat at the 1945 general election.