It was always a marginal seat during this period, but Dame Janet managed to survive many strong challenges at each general election she fought, including winning with a majority of just 34 in October 1974 – making Drake the most marginal Conservative seat at that election.

1918–1950: The County Borough of Plymouth wards of Drake, Mount Edgcumbe, Mutley, Pennycross, St Peter, Stoke, and Valletort.

1974–1983: The County Borough of Plymouth wards of Compton, Drake, Honicknowle, Pennycross, Tamerton, Trelawny, and Whitleigh.

1983–1997: The City of Plymouth wards of Compton, Drake, St Peter, Stoke, Sutton, and Trelawny.

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;