The Middlesex election followed the voiding of the previous election of 1802, which Sir Francis Burdett was declared to have won but which was then contested. In this by-election Burdett was declared to be narrowly defeated as a result of misconduct by the Middlesex sheriffs. The result was subsequently over-turned with Burdett sitting for Middlesex in 1805-1806 only for that result also to be over-turned.

See DNB and The Times, 10 August 1804. See also Godwin's entry for 20 July 1802.