Collated by @HarryHayfield
A list of the reasons for what caused the first by-election in each Parliament since 1950.
1950: Sheffield, Neepsend : Resignation to provide a seat for Solicitor General Frank Soskice
1951: Bournemouth East and Christchurch: Elevation to a hereditary peerage
1955: Mid Ulster: Disqualification
1959: Brighouse and Spenborough: Death
1964: Leyton: Life Peerage to provide seat for Foreign Secretary Patrick Gordon Walker
1966: Carmarthen: Death
1970: St. Marylebone: Life Peerage on appointment as Lord Chancellor
February 1974: Newham South: Life Peerage on appointment as Lord Chancellor
October 1974: Woolwich West: Death
1979: Manchester Central: Life Peerage
1983: Penrith and the Border: Hereditary peerage on appointment as Leader of the House of Lords
1987: Kensington: Death
1992: Newbury: Death
1997: Uxbridge: Death
2001: Ipswich: Death
2005: Cheadle: Death
2010: Oldham East and Saddleworth: Election Petition
2015; Oldham West & Royton; Death
