The 2023 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. It is the first review of Westminster boundaries to be successfully implemented since 2010. These constituencies were first contested at the 2024 general election.
Legal basis 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.
Individual registration The 2023 review was the successor to the 2018 periodic review of Westminster constituencies, which was abandoned after it failed to pass into law. After abandonment of several previous reviews since 2015, the 2023 review was set to be the first review based on electoral registers drawn up using Individual Electoral Registration, which Parliament approved from 2014 to 2015. Because every routine canvass by local government reaches slightly fewer imminent attainers of the age of 18 than the previous system of household registration, the new system favours the Conservatives, according to a University of Manchester researcher in 2023. Local election offices are funded to implement mitigating measures to minimise any such disproportionate impacts. The Command Papers were sponsored and ordered by the Deputy Prime Minister of the Cameron-Clegg coalition, Nick Clegg, a Liberal Democrat.
Process 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).
A description of the review process is detailed in timeline of the 2023 periodic review of Westminster constituencies.
Size of constituencies The four boundary commissions 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.
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.
Distribution of seats
United Kingdom The 650 constituencies were allocated between the four nations of the UK in accordance with the Sainte-Laguë method as shown in the table below. NationPre-review 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 Boundary Commission for England applied the same distribution formula to the English allocation, which results in the following redistribution of constituencies among the English regions: RegionPre-review seats(2010–2019)ElectorateAllocationChangeAverage sizeEast Midlands463,481,12647+174,067Eastern584,482,12761 +373,477London735,550,45475+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
Final proposals
All four commissions submitted their Final Recommendations Reports to the speaker of the House of Commons on 27 June 2023. These were immediately laid before Parliament and the reports were published on the respective commissions' websites on 28 June 2023.
England The final recommendations for England resulted in only 55 of the existing 533 constituencies remaining completely unchanged. +Regional summaryRegionTotal proposedseatsUnchangedSub-regionsEast Midlands47 (+1)7DerbyshireLeicestershire, Lincolnshire and Rutland (+1)NorthamptonshireNottinghamshireEastern61 (+3)3Bedfordshire and Hertfordshire (+1)Cambridgeshire (+1)EssexNorfolk and Suffolk (+1)London75 (+2)3North East LondonNewham and Tower Hamlets (+1)North Central LondonNorth West LondonSouth West LondonSouth Central London (+1)South East LondonNorth East27 (−2)2North of Tyne (−1)North East (−1)Tees ValleyNorth West73 (−2)12Cheshire and MerseysideCumbria and Lancashire (−2)Greater ManchesterSouth East91 (+7)14Berkshire, Hampshire, and Surrey (+2)Buckinghamshire (+1)East Sussex and West Sussex (+1)Isle of Wight (+1)Kent (+1)Oxfordshire (+1)South West58 (+3)2Avon, Somerset, and Devon (+2)CornwallDorsetGloucestershire and Wiltshire (+1)West Midlands57 (−2)8Birmingham and SolihullCoventryHerefordshireShropshireStaffordshire and the Black Country (−2)WarwickshireWorcestershireYorkshire and the Humber54 (–)4Humberside and South Yorkshire (−1)North Yorkshire and West Yorkshire (+1)Total54355
In Wales, 21 of the 32 seats were unaltered from the revised proposals; 10 had revised boundaries (of which five were renamed); and one had a name change only. In Scotland boundary changes affected 18 seats, of which 12 were renamed. Only name changes affected a further six, leaving 33 unaltered. In Northern Ireland, minor boundary changes affected five seats, with no changes to the proposed names.
Northern Ireland As the number of constituencies in Northern Ireland remains the same, changes were only necessary to bring some of the electorates within the permitted range and align boundaries with those of revised local government wards. Belfast South was enlarged into the countryside and renamed Belfast South and Mid Down. East Antrim was extended further west, while Fermanagh and South Tyrone was extended further east into County Armagh.
Demographic changes from new boundaries This table describes how the demographics of each constituency are different under the new boundaries compared to the old boundaries. The population disparity between constituencies exists because boundaries are drawn based on electorate size, not total population. Constituency Catholic Protestant No religion Other religion Total population Old lines New lines Old lines New lines Old lines New lines Old lines New lines Old lines New linesBelfast East10,679 (11.01%)13,111 (12.82%)51,872 (53.85%)52,964 (51.79%)31,792 (33.01%)33,851 (33.10%)1,981 (2.06%)2,349 (2.30%)96,324102,275Belfast North46,485 (42.45%)47,822 (44.91%)37,090 (33.87%)33,686 (31.63%)23,615 (21.56%)22,712 (21.33%)2,317 (2.12%)2,269 (2.13%)109,507106,489Belfast South and Mid Down44,768 (38.16%)44,328 (37.08%)32,208 (27.45%)34,829 (29.13%)34,845 (29.70%)34,928 (29.22%)5,499 (4.69%)5,465 (4.57%)117,320119,950Belfast West69,641 (74.38%)71,640 (69.43%)11,738 (12.54%)17,426 (16.89%)10,606 (11.33%)12,446 (12.06%)1,642 (1.75%)1,665 (1.61%)93,627103,177East Antrim15,709 (17.55%)17,065 (17.60%)48,378 (54.06%)53,436 (55.11%)24,428 (27.30%)25,458 (26.26%)977 (1.09%)995 (1.03%)89,49296,954East Londonderry39,144 (39.26%)41,106 (39.80%)43,277 (43.40%)44,461 (43.05%)16,548 (16.42%)16,962 (16.60%)745 (0.75%)756 (0.73%)99,714103,285Fermanagh and South Tyrone60,742 (55.62%)64,271 (57.49%)35,406 (32.42%)34,501 (30.86%)12,087 (11.07%)12,021 (10.75%)973 (0.89%)997 (0.89%)109,208111,790Foyle72,966 (70.40%)69,411 (71.33%)18,332 (17.69%)16,241 (16.69%)11,279 (10.88%)10,620 (10.91%)1,075 (1.04%)1,033 (1.06%)103,65297,305Lagan Valley22,185 (19.68%)23,802 (21.25%)60,598 (53.77%)59,416 (53.05%)28,239 (25.06%)27,255 (24.33%)1,685 (1.50%)1,537 (1.37%)112,707112,010Mid Ulster69,196 (65.10%)66,568 (63.26%)27,466 (25.84%)28,847 (27.41%)9,063 (8.53%)9,245 (8.79%)560 (0.53%)570 (0.54%)106,285105,230Newry and Armagh77,515 (62.99%)71,766 (64.22%)31,766 (25.81%)27,189 (24.33%)12,822 (10.42%)11,881 (10.63%)950 (0.77%)911 (0.82%)123,053111,747North Antrim29,679 (26.44%)28,245 (27.20%)61,784 (55.04%)56,171 (54.10%)12,822 (17.86%)11,881 (18.01%)950 (0.67%)911 (0.69%)112,262103,831North Down9,959 (10.69%)10,352 (10.57%)49,817 (55.04%)52,671 (54.10%)32,184 (17.86%)33,627 (18.01%)1,210 (0.67%)1,248 (0.69%)93,17097,898South Antrim32,530 (30.58%)31,490 (29.58%)48,559 (45.64%)49,475 (46.48%)24,078 (22.63%)24,286 (22.82%)1,123 (1.12%)1,190 (1.15%)106,390106,441South Down74,536 (65.22%)68,036 (64.65%)25,242 (22.09%)24,284 (23.07%)13,780 (12.06%)12,249 (11.64%)727 (0.64%)672 (0.64%)114,285105,241Strangford14,195 (15.15%)20,494 (20.88%)52,951 (56.53%)51,089 (52.05%)25,555 (27.28%)25,622 (26.10%)967 (1.03%)949 (0.97%)93,66898,154Upper Bann54,172 (41.82%)50,007 (40.98%)50,581 (39.05%)48,722 (39.92%)23,069 (17.81%)21,686 (17.77%)1,699 (1.31%)1,624 (1.33%)129,521122,039West Tyrone61,050 (65.65%)65,634 (65.80%)23,929 (25.73%)25,585 (25.65%)7,470 (8.03%)7,961 (7.98%)541 (0.58%)573 (0.57%)92,99099,753
Scotland
The following table details the proposed changes, based on the commission's final report. + Regional summary Grouping of council areas Number of constituencies Number unchanged Aberdeen City2 (–)0 Aberdeenshire, Argyll and Bute, Highland, and Moray 7 (−1) 1 Angus, Clackmannanshire, Dundee City, Falkirk, Fife, Perth and Kinross, Stirling, and West Lothian 13 (–) 0 Dumfries and Galloway, East Dunbartonshire, North Lanarkshire, Scottish Borders, South Lanarkshire, and West Dunbartonshire 12 (–) 1 City of Edinburgh, East Lothian, and Midlothian 7 (–) 1 East Ayrshire, North Ayrshire, and South Ayrshire 4 (–) 4 East Renfrewshire 1 (–) 1 Glasgow City, Inverclyde, and Renfrewshire 9 (−1) 0 Na h-Eileanan an Iar, Orkney Islands and Shetland Islands 2 (protected) 2
Wales The final recommendations on the new constituencies in Wales were published on 28 June 2023 by the Boundary Commission for Wales. This followed years of proposals and consultations since 2021, with initial proposals published in 2021 and revised in 2022.
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