In the United Kingdom, the boundary commissions are non-departmental public bodies responsible for determining the boundaries of parliamentary constituencies for elections to the House of Commons. There are four boundary commissions: one each for England, Scotland, Wales and Northern Ireland.
Over the history of the House of Commons, the number of Members of Parliament (MPs) has varied for assorted reasons, with increases in recent years due to increases in the population of the United Kingdom. There are currently 650 constituencies, each sending one MP to the House of Commons, corresponding to approximately one for every 92,000 people, or one for every 68,000 parliamentary electors.
In the United Kingdom (UK), each of the electoral areas or divisions called constituencies elects one member to the House of Commons.
East Yorkshire was a county constituency for the House of Commons of the Parliament of the United Kingdom, established for 1997 general election. It elected one Member of Parliament (MP) at least once every five years by the first-past-the-post electoral system. The constituency represented northern part of the East Riding of Yorkshire county.
Hertsmere is a constituency in Hertfordshire, England, represented in the House of Commons since 2015 by Sir Oliver Dowden of the Conservative Party, who is the former deputy prime minister.
Huntingdon is a constituency west of Cambridge in Cambridgeshire and including its namesake town of Huntingdon. It has been represented in the House of Commons of the UK Parliament since 2024 by Ben Obese-Jecty of the Conservative Party.
The Parliament of the United Kingdom currently has 650 parliamentary constituencies across the constituent countries, each electing a single member of parliament (MP) to the House of Commons by the plurality (first-past-the-post) voting system, ordinarily every five years. Voting last took place in all 650 of those constituencies at the United Kingdom general election on 4 July 2024.
Thornbury and Yate is a constituency represented in the House of Commons of the UK Parliament since the 2024 election by Claire Young, a member of the Liberal Democrats. Encompassing an area to the north-east of Bristol, it is one of three constituencies that make up the South Gloucestershire Unitary Authority Area, along with Filton and Bradley Stoke and Kingswood.
Scottish Westminster constituencies were Scottish constituencies of the House of Commons of the Parliament of Great Britain, normally at the Palace of Westminster, from 1708 to 1801, and have been constituencies of the House of Commons of the Parliament of the United Kingdom, also at Westminster, since 1801. Constituency boundaries have changed on various occasions, and are now subject to both periodical and ad hoc reviews of the Boundary Commission for Scotland.
The Senedd constituencies and electoral regions are the electoral districts used to elect members of the Senedd to the Senedd, and have been used in some form since the first election of the then National Assembly for Wales in 1999. New boundaries were introduced for the 2007 elections and currently consist of forty constituencies and five regions. The five electoral regions are: Mid and West Wales, North Wales, South Wales Central, South Wales East, and South Wales West, with the forty constituencies listed below. Voting last took place in all districts in the 2021 Senedd election, and is not used for local government.
The fifth periodic review of Westminster constituencies was undertaken between 2000 and 2007 by the four boundary commissions for England, Scotland, Wales and Northern Ireland for the UK Parliament. The changes for England, Wales and Northern Ireland took effect at the 2010 general election; that for Scotland took effect at the 2005 election. All of the recommendations were approved.
The House of Commons Act 1949 was an Act of the Parliament of the United Kingdom that provided for the periodic review of the number and boundaries of parliamentary constituencies.
The Parliamentary Voting System and Constituencies Act 2011(c. 1) is an Act of the Parliament of the United Kingdom that made provision for the holding of a referendum on whether to introduce the Alternative Vote system in all future general elections to the UK Parliament and also made provision on the number and size of parliamentary constituencies. The Bill for the Act was introduced to the House of Commons on 22 July 2010 and passed third reading on 2 November by 321 votes to 264. The House of Lords passed the Bill, with amendments, on 14 February 2011, and after some compromises between the two Houses on amendments, it received Royal Assent on 16 February 2011.
The 2013 periodic review of Westminster constituencies, also known as the sixth review, was an ultimately unfruitful cycle of the process by which constituencies of the House of Commons of the United Kingdom are reviewed and redistributed. The four UK boundary commissions carried out their reviews between 2011 and 2013, but their recommendations were not taken up by the government and instead the 2018 periodic review of Westminster constituencies was carried out from 2016 to 2018. That review was also not implemented and its results were formally laid aside in 2020.
The second periodic review of Westminster constituencies was undertaken between 1965 and 1969 by the four boundary commissions for England, Scotland, Wales and Northern Ireland for the United Kingdom Parliament as provided by the House of Commons Act 1949 and amended by House of Commons Act 1958. The changes to the constituencies were approved in 1970 and took effect at the February 1974 United Kingdom general election.
The 2023 periodic review of Westminster constituencies was the most recent cycle of the process to redraw the constituency map for the House of Commons of the United Kingdom. The new constituency boundaries were approved by the Privy Council on 15 November 2023 and came into law on 29 November.
The ceremonial county of Buckinghamshire, which comprises the unitary authorities of Buckinghamshire Council and the city of Milton Keynes, currently returns eight MPs to the UK Parliament.
The ceremonial county of Hertfordshire has returned 12 MPs to the UK Parliament since 2024.
The 2018 periodic review of Westminster constituencies was an ultimately unfruitful cycle of the process by which constituencies of the House of Commons of the United Kingdom are reviewed and redistributed. The four UK boundary commissions carried out their reviews between 2016 and 2018, but their recommendations were not taken up by the government and were formally laid aside in 2020.
This article covers the timeline of the most recent cycle of the process to redraw the constituency map for the House of Commons, namely the 2023 Periodic Review of Westminster constituencies. The new constituency borders came into law on 29 November 2023. For a summary of the outcome of the review, see 2023 Periodic Review of Westminster constituencies.
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