In the 2005 general election, the victorious Liberal Democrats candidate in Taunton required the smallest percentage swing from the Conservative MP for them to take the seat.

1983–2010: The Borough of Taunton Deane, and the District of West Somerset wards of Dulverton and Brushford, Exmoor, Haddon, and Quarme.

Labouchere was appointed as vice-president of the Board of Trade, and Master of the Mint, requiring a by-election.

Bainbridge resigned by accepting the office of Steward of the Chiltern Hundreds, causing a by-election.

On petition, Cox's election was scrutinised, and some of his votes were found to have been acquired by bribery, and were then struck off.

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;