A boundary set is established on the date of dissolution following the commencement of the legislation establishing that boundary set. In order to avoid having past and present boundary sets in operation on the day of dissolution, the start date here is the day following dissolution.
The House of Commons Library briefing on constituency boundary reviews and the number of MPs provides background on boundary changes.
- England (start date dependent on next dissolution)
- Northern Ireland (start date dependent on next dissolution)
- Scotland (start date dependent on next dissolution)
- Wales (start date dependent on next dissolution)
- England (13 April 2010 - )
- Northern Ireland (13 April 2010 - )
- Wales (13 April 2010 - )
- Scotland (12 April 2005 - )
- England (9 April 1997 - 12 April 2010)
- Northern Ireland (9 April 1997 - 12 April 2010)
- Scotland (9 April 1997 - 11 April 2005)
- Wales (9 April 1997 - 12 April 2010)
- England (17 March 1992 - 8 April 1997)
- England (14 May 1983 - 16 March 1992)
- Northern Ireland (14 May 1983 - 8 April 1997)
- Scotland (14 May 1983 - 8 April 1997)
- Wales (14 May 1983 - 8 April 1997)
- England (9 February 1974 - 13 May 1983)
- Northern Ireland (9 February 1974 - 13 May 1983)
- Scotland (9 February 1974 - 13 May 1983)
- Wales (9 February 1974 - 13 May 1983)
- England (7 May 1955 - 8 February 1974)
- Scotland (7 May 1955 - 8 February 1974)
- Wales (7 May 1955 - 8 February 1974)
- England (4 February 1950 - 6 May 1955)
- Northern Ireland (4 February 1950 - 8 February 1974)
- Scotland (4 February 1950 - 6 May 1955)
- Wales (4 February 1950 - 6 May 1955)
- England (16 June 1945 - 3 February 1950)
- Northern Ireland (27 October 1922 - 3 February 1950)
- England (26 November 1918 - 15 June 1945)
- Ireland (26 November 1918 - 26 October 1922)
- Scotland (26 November 1918 - 3 February 1950)
- Wales (26 November 1918 - 3 February 1950)