List of United Kingdom Parliament constituencies (1950–1974) by region
South East England (148). Middlesex (28 then 29). Many of these constituencies became part of Greater London when that county was formed in 1965. County of London (43 then 42). See https://commons.wikimedia.org/wiki/Category:Locator_maps_of_former_parliamentary_constituencies_of_England_1948 East Anglia (55). Essex (24 then 26). Seats: Northern Ireland (12). The constituency was won by Philip Clarke of Sinn Féin, but he was unseated on petition on the basis that his criminal conviction (for Irish Republican Army activity) made him ineligible. Instead, the seat was awarded to the Ulster Unionist Party (UUP) candidate. The seat was originally won  by Tom Mitchell of Sinn Féin, but Mitchell was subsequently unseated upon petition, on the grounds that his terrorist convictions made him ineligible to sit in Parliament. The seat was awarded to Charles Beattie of the UUP. However, Beattie in turn was also found ineligible to sit due to holding an office of profit under the crown, triggering a further by-election.