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.
The Representation of the People Act 1948 was an act of the Parliament of the United Kingdom that altered the law relating to parliamentary and local elections. It is noteworthy for abolishing plural voting for parliamentary elections, including by the abolition of the twelve separate university constituencies; and for again increasing the number of members overall, in this case to 613.
The "unreformed House of Commons" is a name given to the House of Commons of Great Britain before it was reformed by the Reform Act 1832, the Irish Reform Act 1832, and the Scottish Reform Act 1832.
The Redistribution of Seats Act 1885 was an Act of the Parliament of the United Kingdom. It was a piece of electoral reform legislation that redistributed the seats in the House of Commons, introducing the concept of equally populated constituencies, a concept in the broader global context termed equal apportionment, in an attempt to equalise representation across the UK. It mandated the abolition of constituencies below a certain population threshold. It was associated with, but not part of, the Representation of the People Act 1884.
The Act of Union 1707 and pre-Union Scottish legislation provided for 14 Members of Parliament (MPs) from Scotland to be elected from districts of burghs. All the parliamentary burghs were assigned to a district, except for Edinburgh which had an MP to itself. The burghs in a district were not necessarily adjacent or even close together.
Duncairn, a division of the parliamentary borough of Belfast, was a UK parliamentary constituency in Ireland. It returned one Member of Parliament (MP) to the House of Commons of the United Kingdom from 1918 to 1922, using the first past the post electoral system.
Tain Burghs was a constituency of the House of Commons of the Parliament of Great Britain from 1708 to 1801 and of the Parliament of the United Kingdom from 1801 to 1832, sometimes known as Northern Burghs. It was represented by one Member of Parliament (MP).
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.
Barnet was a parliamentary constituency in what is now the London Borough of Barnet, which returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom.
Multi-member constituencies existed in the Parliament of the United Kingdom and its predecessor bodies in the component parts of the United Kingdom from the earliest era of elected representation until they were abolished by the Representation of the People Act 1948. Since the 1950 general election, all members of the House of Commons have been elected from single-member constituencies.
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.
Birmingham Moseley was a constituency of the House of Commons of the Parliament of the United Kingdom from 1918 to 1950. It elected one Member of Parliament (MP) by the first-past-the-post system of election.
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 ceremonial county of Cheshire, which comprises the unitary authorities of Cheshire East, Cheshire West and Chester, Halton and Warrington, returned 11 MPs to the UK Parliament from 1997 to 2024. Under the 2023 review of Westminster constituencies, coming into effect for the 2024 general election, the boundary commission proposed 12 constituencies, including two which crossed the border into the county of Merseyside.
