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 review of Westminster constituencies.
Summary The process for periodic reviews of parliamentary constituencies in the United Kingdom is governed by the Parliamentary Constituencies Act 1986, as amended by the Parliamentary Voting System and Constituencies Act 2011 and subsequently by the Parliamentary Constituencies Act 2020. This review was the successor to the 2018 periodic review of Westminster constituencies, which was ultimately abandoned after it failed to pass into law. After abandonment of the previous reviews since 2015, the review is set to be the first review based on electoral registers drawn up using Individual Electoral Registration which Parliament approved from 2014–15, an anti-fraud and personally empowering system in place in most of the world, replacing household registration condemned by the worldwide Office for Democratic Institutions and Human Rights (OSCE/ODIHR). By every, routine, local government canvass reaching slightly fewer imminent attainers of the age of 18 effectively than the old system of household registration a small group of LSE experts have blogged, this change very marginally favours the Conservatives. Local election offices are funded to implement mitigating measures to minimise any such disproportionate impacts. The Command Papers were sponsored and ordered by a Deputy Prime Minister, Nick Clegg, a Liberal Democrat.
Under current legislation, the four Boundary Commissions of the United Kingdom were required to report on their next review of the boundaries of parliamentary constituencies before 1 July 2023. In order to meet this deadline, the Commissions began their work on 5 January 2021. Following three rounds of public consultation, all four Commissions submitted their final proposals to the Speaker of the House of Commons on 27 June 2023. The Speaker immediately laid these before Parliament and the reports were published on the respective Commissions' websites the following day. The new boundaries were formally introduced into UK law on 15 November 2023 through The Parliamentary Constituencies Order 2023. (The original deadline of the end of October was missed by the government, which, according to the Act, must only happen in exceptional circumstances).
Previous reviews The 2013 periodic review of Westminster constituencies was launched by the Parliamentary Voting System and Constituencies Act 2011. The process began in 2011 and was intended to be completed by 2013, but a January 2013 vote in the House of Commons temporarily stopped the process. The 2018 periodic review of Westminster constituencies commenced following the 2015 general election and the four Boundary Commissions submitted their final recommendations to the Secretary of State on 5 September 2018 and made their reports public a week later. Leader of the House of Commons Andrea Leadsom told the House on 13 September 2018 that "it will be some time" before the necessary statutory instruments would be put forward for approval by both the Commons and the Lords.Business of the House – Hansard hansard.parliament.uk The proposals were never put forward for approval before the calling of the general election held on 12 December 2019, and in December 2020 the reviews were formally abandoned under the Schedule to the Parliamentary Constituencies Act 2020.
Proposed changes The Government's policy position regarding the process for the 2023 review was confirmed in a written statement, entitled Strengthening Democracy, by Minister of State for the Cabinet Office Chloe Smith on 24 March 2020. Smith confirmed in her written statement that primary legislation would be brought forward to remove the legal requirement to give effect to the recommendations of the Sixth Review and set the framework for future boundary reviews.
The main proposals in the statement were as follows:
Maintaining 650 seats Under the legislation which governed the unimplemented 2018 Boundary Review recommendations, the number of constituencies was to be reduced from 650 to 600. It was proposed that this be retained at 650, on the grounds that Parliament had a greater workload following the UK's departure from the European Union. Electoral quota tolerance It was proposed to maintain the current tolerance of ±5% from the average size of constituencies (the "electoral quota"). Protected constituencies It was initially proposed that there would be no change to the four protected constituencies of Isle of Wight (divided into two seats), Na h-Eileanan an Iar (the Western Isles of Scotland) and Orkney and Shetland (the Northern Isles of Scotland), which are protected from the electoral quota due to their unique geography. However, during the passage of the legislation, an amendment was introduced to add Ynys Môn (the Isle of Anglesey in Wales), increasing the number of protected constituencies to five. Boundary review cycle It was proposed that reviews be carried out every eight years, rather than the pre-2020 requirement of five years. Implementation of recommendations Under the law as it existed prior to 2020, the final proposals of the Boundary Commissions were brought into effect through an Order in Council that had to be approved by Parliament. It was proposed that the Order in Council should no longer require parliamentary approval.
Legislation A bill was introduced on 19 May 2020 to reflect the written statement and it received its Second Reading on 2 June 2020. The Parliamentary Constituencies Act 2020 received royal assent on 14 December 2020. The Act amends the regulations underpinning the boundary review process, including the Parliamentary Constituencies Act 1986, Northern Ireland Act 1998, Boundary Commissions Act 1992 and Parliamentary Voting System and Constituencies Act 2011.
Commencement of reviews The four Boundary Commissions formally launched their 2023 reviews on 5 January 2021, to coincide with the release by the Office for National Statistics (ONS) of electorate data from analysis of the electoral registers that had been published on 2 March 2020. The commissions jointly calculated the relevant electoral quota/range to be used for the 2023 review and the allocation of parliamentary constituencies between the four nations. The English commission further divided its allocation between the nine regions of England.
Size of constituencies The electorate of the United Kingdom, comprising 650 constituencies, as determined by the ONS, was 47,558,398 on 2 March 2020. The electorate of the five protected constituencies – Isle of Wight (two seats), Na h-Eileanan an Iar, Orkney and Shetland, and Ynys Môn – amounted to 220,132, leaving 47,338,266 to be distributed between the remaining 645 constituencies, which gave an electoral quota of 73,393. Each non-protected constituency must have an electorate which is within 5% of this quota, which gave a permitted range of 69,724 to 77,062. In Northern Ireland the legislation allows for a wider range, in certain prescribed circumstances, from 68,313 to 77,062.
Of the 646 unprotected constituencies (Isle of Wight currently has only one seat), 236 had electorates within the permitted range, while 203 were below and 207 were above.
The regional distribution of these seats is shown in the following table.
Region/NationBelow rangeWithin rangeAbove rangeTotal seatsEastern7252658East Midlands7172246London20203373North East216229North West28331475South East *2374483South West7232555West Midlands2526859Yorkshire and the Humber16221654England133209190532Northern Ireland68418Scotland27181257Wales371139Total203236207646
Distribution of seats
United Kingdom The 650 constituencies were allocated between the four nations of the UK in accordance with the method of allocation specified by the legislation as shown in the table below. NationCurrent seats(2010–2019)Unprotected seatsProtected seatsTotalElectorateAllocationAverage sizeElectorateAllocationElectorateAllocationChangeEngland53339,748,70554173,473111,716239,860,421543+10Northern Ireland181,295,6881871,983--1,295,68818-Scotland594,023,6115573,15756,00124,079,61257-2Wales402,270,2623173,23452,41512,322,67732-8Total65047,338,26664573,393220,132547,558,398650-
Regions of England
The Commission for England applied the same distribution formula to the English allocation, which results in the following redistribution of constituencies among the English regions: RegionCurrent seats(2010–2019)ElectorateAllocationChangeAverage sizeEast of England584,482,12761+373,477East Midlands463,481,12647+174,067London735,550,45475+274,006North East291,952,99927−272,333North West755,381,54973−273,720South East *836,522,80289+673,290South West554,242,13658+373,140West Midlands594,169,01257−273,141Yorkshire and the Humber543,966,50054—73,454Unprotected seats53239,748,705541+973,428Isle of Wight1111,7162+155,858Total53339,860,421543+1073,408 * Excluding Isle of Wight
Comparison with the Fifth Review The current constituency boundaries were largely based on the Fifth Periodic Review of Westminster Constituencies which was carried out by the Boundary Commissions between 2000 and 2007. The Scottish review was completed in time for the 2005 general election, with the other three reviews coming into effect at the 2010 general election. In England, the fifth review was based on the number of electors on the electoral register published in February 2000. The electorates were therefore already 10 years out of date by the time it came into effect, and over 20 years had elapsed between the publication of that register and the start of the 2023 reviews.
The table below shows the movements in the national/regional electorates since those used for the fifth review. Region/NationElectorate in 2000Electorate in 2020Absolute% increaseRelative% increaseEast of England4,063,5944,482,12710.3%2.8%East Midlands3,198,2143,481,1268.8%1.4%London4,974,0255,550,45411.6%4.0%North East1,955,3361,952,999 -0.1% -6.9%North West5,193,0175,381,5493.6% -3.4%South East6,021,1306,634,51810.2%2.7%South West3,779,9704,242,13612.2%4.6%West Midlands4,023,7084,169,0123.6% -3.5%Yorkshire and the Humber3,786,5013,966,5004.8% -2.4%England36,995,49539,860,4217.7%0.4%Northern Ireland1,097,4501,295,68818.1%10.0%Scotland3,995,4894,079,6122.1% -4.9%Wales2,225,5992,322,6774.4% -2.8%Total44,314,03347,558,3987.3%0.0%
Prospective wards The detailed constituency and ward electorates issued by the ONS were based on the local authority boundaries which were currently effective and did not take account of prospective changes which were to be enacted on 1 December 2020. There were 31 such local authorities in England, of which 16 were London boroughs. The Commission for England subsequently worked with local authorities to produce updated data which included these 'prospective' wards. A comprehensive list of ward electorates was published on 24 March 2021.
Timetable The initial outline timetable published by the Commission for England was as follows:
5 January 2021: Begin development of initial proposals. 10 May 2021: Publish Guide to the 2023 Review. 8 June 2021: Publish initial proposals and conduct eight-week written consultation. 22 February 2022: Publish responses to initial proposals and conduct six-week 'secondary consultation', including between two and five public hearings in each region. 8 November 2022: Publish revised proposals and conduct four-week written consultation. 27 June 2023: Submit and publish final report and recommendations.