In common with metropolitan areas the seat saw major population increase.

Until 1918 it included Chiswick, Acton within the County of London, and part of Hanwell in the rump of dwindling Middlesex.

Hamilton was appointed First Lord of the Admiralty, causing a by-election.

Hamilton is appointed Secretary of State for India, requiring a by-election.

The political parties had been making preparations for an election to take place and by the Autumn of 1939, the following candidates had been selected;