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.
Electorates of the Australian House of Representatives are single member electoral districts for the lower house of the Parliament of the Commonwealth. There are currently 151 electorates.
Islington North is a constituency in Greater London established for the 1885 general election. It has been represented in the House of Commons of the UK Parliament since 1983 by Jeremy Corbyn, who was Leader of the Labour Party and Leader of the Opposition from 2015 to 2020. Since 2020, Corbyn has represented the seat as an independent. He was re-elected to Islington North as an independent in the 2024 general election.
In the United Kingdom (UK), each of the electoral areas or divisions called constituencies elects one member to the House of Commons.
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.
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.
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.
In Australia, a redistribution is the process of redrawing the boundaries of electoral divisions for the House of Representatives arising from changes in population and changes in the number of representatives. There is no redistribution for the Senate as each State constitutes a division, though with multiple members. The Australian Electoral Commission (AEC), an independent statutory authority, oversees the apportionment and redistribution process for federal divisions, taking into account a number of factors. Politicians, political parties and the public may make submissions to the AEC on proposed new boundaries, but any interference with their deliberations is considered a serious offence.
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.
Redistribution is the process by which electoral districts are added, removed, or otherwise changed. Redistribution is a form of boundary delimitation that changes electoral district boundaries, usually in response to periodic census results. Redistribution is required by law or constitution at least every decade in most representative democracy systems that use first-past-the-post or similar electoral systems to prevent geographic malapportionment. The act of manipulation of electoral districts to favour a candidate or party is called gerrymandering.
The House of Commons Act 1944 was an Act of the Parliament of the United Kingdom that established permanent boundary commissions for each of the constituent countries of the United Kingdom, and 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 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.
The county of Northumberland has returned four MPs to the UK Parliament since 1983. Under the 2023 review of Westminster constituencies, coming into effect for the 2024 general election, the boundary commission proposed that two of the four constituencies be shared with the county of Tyne and Wear.
The county of Durham returned 7 MPs to the UK Parliament from 1983 to 2024. Under the 2023 review of Westminster constituencies, coming into effect for the 2024 general election, the boundary commission proposed that one constituency be shared with the county of Tyne and Wear. In addition, the unitary authority of Darlington, which had previously been included with Durham, was now included with the four unitary authorities which make up the former county of Cleveland. For the purposes of this series of articles, Darlington continues to be included with Durham.
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.
