Following the passage of the Parliamentary Voting System and Constituencies Act, the four national Boundary Commissions were asked to undertake the "2018 Review" of contituency boundaries to equalise the size of seat both within and between the four nations of the UK. The Boundary Commissions are independent bodies who put considerable effort into drawing up boundaries in a generally fair way, reflecting local geography and affiliations. There are two consultation periods where comments and objections to the proposals can be brought forward for consideration.
The Boundary Commission of England published its initial set of proposals on 13 September 2016, with final proposals being ready by September 2018. The Welsh Boundary Commission also published their initial proposals on the same day. The Boundary Commission for Northern Ireland published its initial proposals on 6 September 2016. The Scottish Boundary Commission is published its initial proposals on 20 October 2016.
Revised proposals were published by the English, Scottish and Welsh Boundary Commissions on 17 October 2017. Revised proposals were published by the Northern Ireland Boundary Commission in January 2018.
Final proposals were published by all four Boundary Commissions on 10 September 2018. The analysis below is based on these final proposals.
Click on the map image to go to a full browsable map of the all the seats with initial proposals.
Press reports in early September 2017 (see Times or Guardian) suggest that the government is unlikely to push forward with the reduction in seats to 600. It is suggested that the Boundary Commissions will be asked to repeat their reviews but keeping the total number of seats at 650.
That will require primary legislation, since the 600 seats are set down in the Parliamentary Voting System and Constituencies Act 2011. If new legislation is brought forward it could usefully also change the electorate tolerances from 5pc to 10pc, as this would make seats more homogeneous and reduce the need to cross traditional boundaries.
A repeat of the reviews could not be done very quickly, since all the proposed boundaries would have to be redrawn and the consultation processes re-run on the new boundaries.
Taken together, this greatly increases the chances that the next general election will be run under the existing boundaries.
The total number of seats per consituent part of the country is already known:
|Area||Old Seats||New Seats||Change|
This page contains full details of these reviews as they are published.
The Boundary Commissions have now all published their initial proposals. This allows us to get a good overall view of the likely outcome. In terms of the headline impact on seats nationally the implied result of the 2017 general election, as if it had been run under the new boundaries, is:
election result 2017
|Implied result at 2017|
under new boundaries
|Net Change||Disappear||Switch Out||Switch In||Fresh|
The Conservatives would change from being 8 seats short of a majority to having a majority of eighteen seats. If they continued to have an alliance with the DUP, their total majority would have increased from six to thirty-eight.
The analysis below shows which seats "disappear" under the boundary changes, which seats switch party allegiance, and which fresh seats are newly created.
Area by area, the net change in seats is shown in this table:
|Region||Old Seats||New Seats||Change||CON||LAB||LIB||UKIP||Green||NAT||MIN|
There are full regional pages of explanation and seat breakdowns available. Just click on the region's name in the left-hand column of the table.
Generally, the regions of northern England and London lose the most seats, while southern England loses fewer seats. Since the former regions are more Labour-leaning than the latter, this is the main driver for the relatively larger losses of Labour seats.
For each proposed new seat, we define the predecessor seat to be the old seat which contributes the most voters to that new seat. Old seats which are not the predecessor of any new seat are said to "disappear". This means that they are split into fragments, and none of those fragments forms the largest part of any new seat.
There are 58 disappearing seats across the country, shown in the table below:
|Old Seat||Party||Current MP||County/Area|
|Aberavon||LAB||Stephen Kinnock||West Glamorgan (Wales)|
|Aberconwy||CON||Guto Bebb||Clwyd (Wales)|
|Aberdeenshire West and Kincardine||CON||Andrew Bowie||Grampian (Scotland)|
|Airdrie and Shotts||SNP||Neil Gray||Glasgow area (Scotland)|
|Antrim South||DUP||Paul Girvan||Antrim (Northern Ireland)|
|Arfon||Plaid||Hywel Williams||Gwynedd (Wales)|
|Ayrshire Central||SNP||Philippa Whitford||Ayrshire and Lanark (Scotland)|
|Birmingham Perry Barr||LAB||Khalid Mahmood||Birmingham (West Midlands)|
|Bradford East||LAB||Imran Hussain||West Yorkshire (Yorks/Humber)|
|Cardiff Central||LAB||Jo Stevens||South Glamorgan (Wales)|
|Carmarthen West and Pembrokeshire South||CON||Simon Hart||Dyfed (Wales)|
|Chelsea and Fulham||CON||Greg Hands||Hammersmith and Fulham (London)|
|Cornwall North||CON||Scott Mann||Cornwall (South West)|
|Delyn||LAB||David Hanson||Clwyd (Wales)|
|Derbyshire Mid||CON||Pauline Latham||Derbyshire (East Midlands)|
|Dorset North||CON||Simon Hoare||Dorset (South West)|
|Dudley North||LAB||Ian Austin||Black Country (West Midlands)|
|Dulwich and West Norwood||LAB||Helen Hayes||Lambeth (London)|
|Durham, City of||LAB||Roberta Blackman-Woods||Durham (North East)|
|Edinburgh South West||SNP||Joanna Cherry||Edinburgh area (Scotland)|
|Erith and Thamesmead||LAB||Teresa Pearce||Bexley (London)|
|Faversham and Kent Mid||CON||Helen Whately||Kent (South East)|
|Finchley and Golders Green||CON||Mike Freer||Barnet (London)|
|Glasgow Central||SNP||Alison Thewliss||Glasgow area (Scotland)|
|Gower||LAB||Tonia Antoniazzi||West Glamorgan (Wales)|
|Great Grimsby||LAB||Melanie Onn||Humber area (Yorks/Humber)|
|Hackney North and Stoke Newington||LAB||Diane Abbott||Hackney (London)|
|Haltemprice and Howden||CON||David Davis||Humber area (Yorks/Humber)|
|Herefordshire North||CON||Bill Wiggin||Hereford and Worcestershire (West Midlands)|
|Islwyn||LAB||Chris Evans||Gwent (Wales)|
|Kenilworth and Southam||CON||Jeremy Wright||Warwickshire (West Midlands)|
|Lancaster and Fleetwood||LAB||Cat Smith||Lancashire (North West)|
|Leeds West||LAB||Rachel Reeves||West Yorkshire (Yorks/Humber)|
|Leyton and Wanstead||LAB||John Cryer||Waltham Forest (London)|
|Liverpool Walton||LAB||Dan Carden||Merseyside (North West)|
|Meon Valley||CON||George Hollingbery||Hampshire (South East)|
|Middlesbrough South and Cleveland East||CON||Simon Clarke||Teesside (North East)|
|Montgomeryshire||CON||Glyn Davies||Powys (Wales)|
|Newcastle upon Tyne North||LAB||Catherine McKinnell||Newcastle area (North East)|
|Newport East||LAB||Jessica Morden||Gwent (Wales)|
|Nottingham East||LAB||Chris Leslie||Nottinghamshire (East Midlands)|
|Ochil and South Perthshire||CON||Luke Graham||Central (Scotland)|
|Penistone and Stocksbridge||LAB||Angela Smith||South Yorkshire (Yorks/Humber)|
|Pontypridd||LAB||Owen Smith||Mid Glamorgan (Wales)|
|Poplar and Limehouse||LAB||Jim Fitzpatrick||Tower Hamlets (London)|
|Ribble Valley||CON||Nigel Evans||Lancashire (North West)|
|Rochdale||LAB||Tony Lloyd||Eastern Manchester (North West)|
|Ross Skye and Lochaber||SNP||Ian Blackford||Highland (Scotland)|
|Stockport||LAB||Ann Coffey||Eastern Manchester (North West)|
|Stockton North||LAB||Alex Cunningham||Teesside (North East)|
|Stone||CON||Bill Cash||Staffordshire (West Midlands)|
|Tatton||CON||Esther McVey||Cheshire (North West)|
|Tunbridge Wells||CON||Greg Clark||Kent (South East)|
|Walsall North||CON||Eddie Hughes||Black Country (West Midlands)|
|Wansbeck||LAB||Ian Lavery||Northumberland (North East)|
|Wirral South||LAB||Alison McGovern||Merseyside (North West)|
|Witham||CON||Priti Patel||Essex (Anglia)|
|Workington||LAB||Sue Hayman||Cumbria (North West)|
If an MP's name is shown here it does not mean that he or she will stop being an MP at the next election. But they have to change the precise area which they represent, and they may be subject to their party's reselection process.
Some new seats have clear predecessor seats, but the boundary changes are large enough that the new seat contains many voters with a different political outlook. This can cause the new seat to have a different predicted party winner from its predecessor. Such seats are called "switching seats", and there are 41 of them:
|Current MP||New seat||New Party||New|
|Barrow and Furness||LAB||John Woodcock||Barrow and Furness||CON||765||Cumbria (North West)|
|Bedford||LAB||Mohammad Yasin||Bedford||CON||84||Bedfordshire (Anglia)|
|Bolton West||CON||Chris Green||Bolton West||LAB||1,624||Western Manchester (North West)|
|Brighton Kemptown||LAB||Lloyd Russell-Moyle||Brighton Kemptown and Seahaven||CON||3,506||East Sussex (South East)|
|Caithness Sutherland and Easter Ross||LIB||Jamie Stone||Highland North||SNP||1,313||Highland (Scotland)|
|Canterbury||LAB||Rosie Duffield||Canterbury and Faversham||CON||3,933||Kent (South East)|
|Carmarthen East and Dinefwr||Plaid||Jonathan Edwards||Carmarthen||LAB||364||Dyfed (Wales)|
|Carshalton and Wallington||LIB||Tom Brake||Carshalton and Wallington||CON||1,036||Sutton (London)|
|Cities of London and Westminster||CON||Mark Field||Cities of London and Westminster||LAB||1,529||City of Westminster (London)|
|Clwyd South||LAB||Susan Elan Jones||Clwyd South and North Montgomeryshire||CON||2,570||Clwyd (Wales)|
|Copeland||CON||Trudy Harrison||Cumbria West||LAB||6,368||Cumbria (North West)|
|Coventry South||LAB||James Cunningham||Coventry South and Kenilworth||CON||3,728||Coventry and Solihull (West Midlands)|
|Crewe and Nantwich||LAB||Laura Smith||Crewe and Nantwich||CON||1,283||Cheshire (North West)|
|Croydon Central||LAB||Sarah Jones||Croydon South East||CON||1,612||Croydon (London)|
|Derby South||LAB||Margaret Beckett||Derby East||CON||2,003||Derbyshire (East Midlands)|
|Down North||MIN||Lady Sylvia Hermon||Down North||DUP||4,317||Down (Northern Ireland)|
|Edinburgh East||SNP||Tommy Sheppard||Edinburgh East||LAB||3,630||Edinburgh area (Scotland)|
|Edinburgh West||LIB||Christine Jardine||Edinburgh West||SNP||862||Edinburgh area (Scotland)|
|Harrow East||CON||Bob Blackman||Harrow North||LAB||2,694||Harrow (London)|
|Keighley||LAB||John Grogan||Keighley||CON||1,578||West Yorkshire (Yorks/Humber)|
|Kensington||LAB||Emma Dent Coad||Kensington and Chelsea||CON||5,258||Kensington and Chelsea (London)|
|Kirkcaldy and Cowdenbeath||LAB||Lesley Laird||Fife South||SNP||121||Fife (Scotland)|
|Lincoln||LAB||Karen Lee||Lincoln and North Hykeham||CON||704||Lincolnshire (East Midlands)|
|Midlothian||LAB||Danielle Rowley||Midlothian and Upper Tweeddale||SNP||1,295||Edinburgh area (Scotland)|
|Morecambe and Lunesdale||CON||David Morris||Lancaster and Morecambe||LAB||5,921||Lancashire (North West)|
|Morley and Outwood||CON||Andrea Jenkyns||Batley and Morley||LAB||5,029||West Yorkshire (Yorks/Humber)|
|Motherwell and Wishaw||SNP||Marion Fellows||Lanarkshire North East||LAB||469||Glasgow area (Scotland)|
|Newcastle-under-Lyme||LAB||Paul Farrelly||Newcastle-under-Lyme||CON||2,538||Staffordshire (West Midlands)|
|Norwich North||CON||Chloe Smith||Norwich North||LAB||1,893||Norfolk (Anglia)|
|Oxford West and Abingdon||LIB||Layla Moran||Abingdon and Oxford North||CON||2,140||Oxfordshire (South East)|
|Perth and North Perthshire||SNP||Pete Wishart||Perth and North Perthshire||CON||53||Tayside (Scotland)|
|Portsmouth South||LAB||Stephen Morgan||Portsmouth South||CON||55||Hampshire (South East)|
|Pudsey||CON||Stuart Andrew||Pudsey||LAB||15,102||West Yorkshire (Yorks/Humber)|
|Southampton Itchen||CON||Royston Smith||Southampton Itchen||LAB||3,583||Hampshire (South East)|
|Stroud||LAB||David Drew||Stroud||CON||861||Gloucestershire (South West)|
|Telford||CON||Lucy Allan||Telford||LAB||209||Shropshire (West Midlands)|
|Uxbridge and South Ruislip||CON||Boris Johnson||Uxbridge and Northolt||LAB||567||Hillingdon (London)|
|Vale of Glamorgan||CON||Alun Cairns||Vale of Glamorgan East||LAB||729||South Glamorgan (Wales)|
|Warwick and Leamington||LAB||Matt Western||Warwick and Leamington||CON||2,235||Warwickshire (West Midlands)|
|Weaver Vale||LAB||Mike Amesbury||Weaver Vale||CON||774||Cheshire (North West)|
|Westmorland and Lonsdale||LIB||Tim Farron||Westmorland and Lonsdale||CON||2,632||Cumbria (North West)|
Notable seats changing hands include many Conservative losses such as the Cities of London and Westminster, the recent by-election gain in Copeland, Ed Balls' old seat of Morley and Outwood, and Norwich North. The Conservatives are slated to regain Kensington
Although the overall change is to reduce the number of seats, there are a few new seats which are freshly created. This means that the new seat is made up of a number of small fragments from various old seats. If the largest component of the new seat is not the largest part of its corresponding old seat, then the seat is defined to be "fresh". There are eight fresh new seats:
|Bramhall and Wilmslow||CON||13,824||Eastern Manchester (North West)|
|Falkirk South||SNP||2,901||Central (Scotland)|
|Great Grimsby North and Barton||CON||6,744||Humber area (Yorks/Humber)|
|Isle of Wight West||CON||9,689||Hampshire (South East)|
|Leyton and Stratford||LAB||33,534||Newham (London)|
|Middlesbrough South and Thornaby||LAB||3,053||Teesside (North East)|
|Shoreditch and Bethnal Green||LAB||37,976||Hackney (London)|
|Weald of Kent||CON||24,637||Kent (South East)|
The Boundary Commission for England published final proposals on 10 September 2018.
The net effect of the changes for England is shown in the following table:
|Old Seats||New Seats||Change||Disappear||Switch Out||Switch In||Fresh|
Full details are available on the area pages: North East, North West, Yorks/Humber, West Midlands, East Midlands, Anglia, South West, London, South East
The Boundary Commission for Wales published final proposals on 10 September 2018.
The net effect of the changes for Wales is shown in the following table:
|Old Seats||New Seats||Change||Disappear||Switch Out||Switch In||Fresh|
Visit the Wales Area page for more details.
The Boundary Commission for Scotland published its final proposals on 10 September 2018.
The net effect of the changes for Scotland is shown in the following table:
|Old Seats||New Seats||Change||Disappear||Switch Out||Switch In||Fresh|
Visit the Scotland Area page for more details.
Final proposals for new parliamentary boundaries were published by the Boundary Commission for Northern Ireland on 10 September 2018. Analysis of these final proposals by Electoral Calculus, assuming that voting patterns remain stable, indicates the the Democratic Unionist Party has improved its position from the initial proposals. The DUP is now predicted to keep its ten seats and continue to be the largest NI party at Westminster. The republican Sinn Féin is also likely to keep its seven seats. The total number of seats in the province decreases from 18 to 17.
The main change is that the DUP gain Down North from independent MP Sylvia Hermon. But the DUP also lose one seat as two of their existing seats (Antrim South and Lagan Valley) are merged together in the new seat of Antrim South.
|Party||Old Seats||New Seats||Change||Commentary|
|DUP||10||10||0||Lose (old) "Antrim South", gain "Down North" from MIN|
|MIN||1||0||−1||Lose "Down North" to DUP|
Visit the Northern Ireland Area page for more details.
The graphic shows that the Conservatives gain about ten seats from Labour due to the new boundaries at current opinion poll levels, or even if Labour increase their lead. But if the Conservatives do better in the polls, then paradoxically they gain less from the new boundaries. If the Conservatives were on course to win the general election, then the "boost" from new boundaries would be only about five seats.
These relatively modest impacts may diminish the political motivation for pushing through these changes.
See also the information about the now-abandoned "Sixth Periodic review", to compare against the 2018 Review.