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. Changes were also made to the constituencies and electoral regions of the then National Assembly for Wales (now the Senedd), and took effect at the 2007 Assembly election. All of the recommendations were approved.
Review process The boundary commissions were required at the time by the Parliamentary Constituencies Act 1986 to review constituencies in their part of the United Kingdom every eight to twelve years. The commissions' recommendations from the review were based on the numbers of electors on the electoral register and ward boundaries at the start of the review in 2000.
In Scotland, the recommendations were submitted in November 2004, and approved in February 2005. In Wales, the recommendations were submitted on 31 January 2005, and approved on 11 April 2006. In England, the recommendations were submitted on 31 October 2006, and approved on 13 June 2007. In Northern Ireland, the recommendations were submitted on 14 September 2007 and approved on 11 June 2008.
Summary of changes
These were the first major changes to UK Parliamentary constituencies since 1997.
As set out in the approval dates above, the Scottish changes were effective from the 2005 general election. The post-2010 shape of those for the rest of the UK can be viewed alongside those for Scotland of 2005 at United Kingdom Parliament constituencies.
A side effect of reviews is the number of seats won by each party may change (even if all voters repeated their votes at later elections).
The total number of Scottish seats dropped from 72 to 59, due to changes made by the Scotland Act 1998, applying the English electoral quota to Scotland. This had reduced total seats back down from 659 to 646, pending the review of the rest of the UK.
In Wales, changes were made not only to the Westminster constituencies but also to the constituencies and electoral regions of the then National Assembly, which at the time used the same constituency boundaries. This was the first time the Assembly's boundaries were changed. The total number of constituencies remained 40, but entailed radical redrawing in Clwyd and in Gwynedd. Aberconwy, Arfon and Dwyfor Meirionnydd replaced Conwy, Caernarfon and Meirionnydd Nant Conwy respectively. 18 seats were unchanged with only minor changes elsewhere. The boundaries of the Assembly's electoral regions were changed accordingly to reflect constituency changes, thusly the only major changes were to the boundary between North Wales and Mid and West Wales. Per 2006 statistics, Welsh constituencies had on average 16,000 fewer electors than those of England.
In Northern Ireland, the Boundary Commission recommended that the number of seats remained at 18, with minor changes to 12 of these, primarily in the east of the province.
In England, the seats recommended seldom straddle the largest council areas, i.e. counties (metropolitan or otherwise); however they may cross boundaries of unitary authorities. York was consolidated to have two seats, without electoral wards from North Yorkshire. The unitary authorities of Berkshire are represented in Westminster by many cross-authority seats.
The Boundary Commission for England created one extra seat each to represent ten non-metropolitan counties: Cornwall, Derbyshire, Devon, Essex, Hampshire, Lancashire, Norfolk, Northamptonshire, Warwickshire and Wiltshire; and one covering the area of the former county of Avon. This was partly offset by the abolition of one seat in each of the six metropolitan counties of Greater Manchester, Merseyside, Tyne and Wear, South Yorkshire, West Midlands and West Yorkshire, together with a net loss of one seat in Greater London.
London was reviewed borough-by-borough – some were "paired". This means they see one or more straddling seats. This solution ensures that the sizes of the electorates are not too disparate, in other words, quite fairly apportioned to reflect the adult resident population. Two boroughs lost a seat and one area of central London gained a constituency.
The approved recommendations for the three countries saw a net increase of 4 seats from 646 to 650 (for the 2010 general election).
Detailed changes – England (2010)
New and abolished constituencies As a result of changes to the names of seats, it is not always easy to clearly identify newly created constituencies or those abolished during the review process. One way of considering this is to link each proposed seat with an existing seat which contributes the most voters to that new seat. Any proposed seat which cannot be linked to an existing seat is then considered to be a "new" constituency. Conversely, any existing seat which is not linked to a proposed seat is considered to have been abolished.
Accordingly, the following seats are regarded as new creations:
Central Devon Chelsea and Fulham Chippenham Filton and Bradley Stoke Kenilworth and Southam Meon Valley Mid Derbyshire Mid Norfolk (as reconfigured) South Northamptonshire St Austell and Newquay Witham Wyre and Preston North
NB – the existing seat of Mid Norfolk is succeeded by Broadland (see below) and the reconfigured Mid Norfolk is therefore considered to be a new constituency.
The following constituencies are regarded as having been abolished by the review process:
Barnsley West and Penistone Birmingham Selly Oak (existing configuration) Brent East Eccles Hornchurch Knowsley North and Sefton East Normanton Sunderland South
NB – the proposed constituency of Birmingham Selly Oak is preceded by the existing constituency of Birmingham Hall Green; and, in turn, the proposed constituency of Birmingham Hall Green is preceded by Birmingham Sparkbrook and Small Heath (see below).
Name changes There was a total of 72 linked constituencies which involved a change of name. A majority of these involved significant changes resulting from the knock-on impact of new or abolished seats within review areas. However, some arose from the consultation process and involved only minor changes. The table below lists those constituencies with name changes, indicating the extent of the changes by reference to the proportion of the old constituency included in the new constituency, or the proportion of the new in the old, which ever is the lesser:
Minor – greater than 90% Moderate – between 75% and 90% Major – between 75% and 50% Wholesale – less than 50%
County/authorityOld seatNew seatExtent of changeBarking and Dagenham/HaveringDagenhamDagenham and RainhamMajorUpminsterHornchurch and UpminsterMajorBath and North East SomersetWansdykeNorth East SomersetModerateBrent/CamdenBrent SouthBrent CentralWholesaleHampstead and HighgateHampstead and KilburnMajorBromley/LewishamLewisham WestLewisham West and PengeMajorCornwallFalmouth and CamborneCamborne and RedruthMajorTruro and St AustellTruro and FalmouthMajorDerbyshireWest DerbyshireDerbyshire DalesMajorDevonTeignbridgeNewton AbbotMajorEaling/HammersmithEaling, Acton and Shepherd's BushEaling Central and ActonMajorEssexBasildonSouth Basildon and East ThurrockMajorBillericayBasildon and BillericayWholesaleHarwichClactonModerateMaldon and East ChelmsfordMaldonMajorNorth EssexHarwich and North EssexMajorRayleighRayleigh and WickfordMajorWest ChelmsfordChelmsfordModerateGloucestershireCotswoldThe CotswoldsMinorGreater ManchesterManchester, BlackleyBlackley and BroughtonMajorSalfordSalford and EcclesMajorWorsleyWorsley and Eccles SouthMajorHammersmith and Fulham/ Kensington and ChelseaHammersmith and FulhamHammersmithMajorKensington and ChelseaKensingtonMajorHampshire/SouthamptonRomseyRomsey and Southampton NorthModerateHarrow/HillingdonRuislip-NorthwoodRuislip, Northwood and PinnerMajorUxbridgeUxbridge and South RuislipMajorHerefordshire/WorcestershireHerefordHereford and South HerefordshireMinorLeominsterNorth HerefordshireModerateKensington and Chelsea/ WestminsterRegent's Park and Kensington NorthWestminster NorthMajorKentGillinghamGillingham and RainhamMinorMedwayRochester and StroodModerateLambeth/SouthwarkNorth Southwark and BermondseyBermondsey and Old SouthwarkMinorLancashire/BlackpoolBlackpool North and FleetwoodBlackpool North and CleveleysMajorLancaster and WyreLancaster and FleetwoodMajorLeicestershireBlabySouth LeicestershireMinorMerseysideCrosbySefton CentralMajorKnowsley SouthKnowsleyMajorLiverpool, GarstonGarston and HalewoodModerateSt Helens SouthSt Helens South and WhistonModerateMilton KeynesNorth East Milton KeynesMilton Keynes NorthModerateMilton Keynes South WestMilton Keynes SouthModerateNewham/Tower HamletsPoplar and Canning TownPoplar and LimehouseMajorNorfolkMid NorfolkBroadlandMajorNorth SomersetWoodspringNorth SomersetMinorNorth Yorkshire/YorkCity of YorkYork CentralModerateRyedaleThirsk and MaltonMajorSelbySelby and AinstyModerateVale of YorkYork OuterWholesalePlymouthPlymouth DevonportPlymouth Moor ViewModeratePlymouth SuttonPlymouth Sutton and DevonportModerateSomersetBridgwaterBridgwater and West SomersetMinorTauntonTaunton DeaneMinorSouth GloucestershireNorthavonThornbury and YateModerateSouth YorkshireBarnsley East and MexboroughBarnsley EastWholesaleSheffield, AttercliffeSheffield South EastMinorSheffield, BrightsideSheffield, Brightside and HillsboroughMajorSheffield, HillsboroughPenistone and StocksbridgeMajorWentworthWentworth and DeaneModerateTyne and WearGateshead East and Washington WestWashington and Sunderland WestWholesaleHoughton and Washington EastHoughton and Sunderland SouthMajorNewcastle upon Tyne East and WallsendNewcastle upon Tyne EastMajorSunderland NorthSunderland CentralMajorTyne BridgeGatesheadWholesaleWarwickshireRugby and KenilworthRugbyMajorWest MidlandsBirmingham, Hall GreenBirmingham, Selly OakWholesaleBirmingham, Sparkbrook and Small HeathBirmingham, Hall GreenWholesaleWest YorkshireBradford NorthBradford EastModerateElmetElmet and RothwellModerateMorley and RothwellMorley and OutwoodMajorPontefract and CastlefordNormanton, Pontefract and Castleford ModerateWiltshireWestburySouth West WiltshireModerate
Other major changes In addition to the changes listed above, the following 45 constituencies were subject to major changes whilst retaining their names. County/authorityConstituencyBarking and Dagenham/HaveringBarkingBrent/CamdenBrent NorthBristolBristol EastBristol North WestBristol WestBromley/LewishamBeckenhamBromley and ChislehurstLewisham EastCornwallNorth CornwallDerbyshireDerby NorthDerby SouthDevonEast DevonTiverton and HonitonEalingEaling, SouthallEssexBraintreeSaffron WaldenGreater ManchesterLeighMakerfieldHampshireEast HampshireNorth East HampshireWinchesterHarrow/HillingdonHarrow WestLambeth/SouthwarkCamberwell and PeckhamLancashireRibble ValleyNewham/Tower HamletsWest HamNorfolkSouth West NorfolkNorthamptonshireDaventryNorthampton SouthSouth GloucestershireKingswoodSouth YorkshireBarnsley CentralDoncaster NorthSheffield CentralSheffield, HallamTyne and WearNewcastle upon Tyne CentralWarwickshireStratford-on-AvonWest MidlandsBirmingham, Hodge HillBirmingham, LadywoodBirmingham, NorthfieldBirmingham, YardleyWest YorkshireDewsburyLeeds CentralLeeds EastWakefieldWiltshireDevizesNorth Wiltshire
Detailed changes – Scotland (2005)