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.
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.
Click on the map image to go to a full interactive map of the all the seats with initial proposals.
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 2015 general election, as if it had been run under the new boundaries, is:
election result 2015
|Implied result at 2015|
under new boundaries
The Conservative majority would increse from 12 seats in the House of Commons to 34.
The analysis below shows which seats "disappear" under the boundary changes, which seats switch party allegiance, and which fresh seats are newly created.
Region by region, 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 59 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)|
|Angus||SNP||Michael Weir||Tayside (East Scotland)|
|Arfon||PC||Hywel Williams||Gwynedd (Wales)|
|Ayrshire Central||SNP||Philippa Whitford||Ayrshire and Lanark (West Scotland)|
|Belfast South||LAB||Dr Alasdair McDonnell||Antrim (Northern Ireland)|
|Birmingham Hall Green||LAB||Roger Godsiff||Birmingham (West Midlands)|
|Bournemouth West||CON||Conor Burns||Dorset (South West)|
|Bradford South||LAB||Judith Cummins||West Yorkshire (Yorkshire)|
|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 (North London)|
|Cornwall North||CON||Scott Mann||Cornwall (South West)|
|Delyn||LAB||David Hanson||Clwyd (Wales)|
|Derbyshire North East||LAB||Natascha Engel||Derbyshire (East Midlands)|
|Dudley North||LAB||Ian Austin||Black Country (West Midlands)|
|Edinburgh South||LAB||Ian Murray||Edinburgh area (East Scotland)|
|Enfield Southgate||CON||David Burrowes||Enfield (North London)|
|Faversham and Kent Mid||CON||Helen Whately||Kent (South East)|
|Gedling||LAB||Vernon Coaker||Nottinghamshire (East Midlands)|
|Glasgow North||SNP||Patrick Grady||Glasgow area (West Scotland)|
|Gower||CON||Byron Davies||West Glamorgan (Wales)|
|Great Grimsby||LAB||Melanie Onn||Humber area (Humberside)|
|Hackney North and Stoke Newington||LAB||Diane Abbott||Hackney (North London)|
|Haltemprice and Howden||CON||David Davis||Humber area (Humberside)|
|Herefordshire North||CON||Bill Wiggin||Hereford and Worcestershire (Severn)|
|Houghton and Sunderland South||LAB||Bridget Phillipson||Newcastle area (North)|
|Ilford South||LAB||Mike Gapes||Redbridge (North London)|
|Islwyn||LAB||Christopher Evans||Gwent (Wales)|
|Kenilworth and Southam||CON||Jeremy Wright||Warwickshire (East Midlands)|
|Kirkcaldy and Cowdenbeath||SNP||Roger Mullin||Fife (East Scotland)|
|Lancaster and Fleetwood||LAB||Catherine Smith||Lancashire (Lancashire)|
|Leeds West||LAB||Rachel Reeves||West Yorkshire (Yorkshire)|
|Lewisham Deptford||LAB||Vicky Foxcroft||Lewisham (South London)|
|Lewisham West and Penge||LAB||Jim Dowd||Lewisham (South London)|
|Liverpool Walton||LAB||Steve Rotheram||Merseyside (Lancashire)|
|Meon Valley||CON||George Hollingbery||Hampshire (South)|
|Middlesbrough||LAB||Andy McDonald||Teesside (North)|
|Mitcham and Morden||LAB||Siobhain McDonagh||Merton (South London)|
|Montgomeryshire||CON||Glyn Davies||Powys (Wales)|
|Motherwell and Wishaw||SNP||Marion Fellows||Glasgow area (West Scotland)|
|Newcastle upon Tyne Central||LAB||Chi Onwurah||Newcastle area (North)|
|Newport East||LAB||Jessica Morden||Gwent (Wales)|
|Oldham East and Saddleworth||LAB||Debbie Abrahams||Eastern Manchester (Greater Manchester)|
|Pendle||CON||Andrew Stephenson||Lancashire (Lancashire)|
|Penistone and Stocksbridge||LAB||Angela Smith||South Yorkshire (Humberside)|
|Pontypridd||LAB||Owen Smith||Mid Glamorgan (Wales)|
|Ross Skye and Lochaber||SNP||Ian Blackford||Highland (East Scotland)|
|Stirling||SNP||Steven Paterson||Central (East Scotland)|
|Stockport||LAB||Ann Coffey||Eastern Manchester (Greater Manchester)|
|Stockton North||LAB||Alex Cunningham||Teesside (North)|
|Stoke-on-Trent Central||LAB||Tristram Hunt||Staffordshire (Severn)|
|Tatton||CON||George Osborne||Cheshire (Severn)|
|Ulster Mid||SF||Francie Molloy||Tyrone (Northern Ireland)|
|Walsall North||LAB||David Winnick||Black Country (West Midlands)|
|Wansbeck||LAB||Ian Lavery||Northumberland (North)|
|Wirral South||LAB||Alison McGovern||Merseyside (Lancashire)|
|Witham||CON||Priti Patel||Essex (Essex)|
|Workington||LAB||Sue Hayman||Cumbria (North)|
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 40 of them:
|Current MP||New seat||New Party||New|
|Amber Valley||CON||Nigel Mills||Alfreton and Clay Cross||LAB||4,615||Derbyshire (East Midlands)|
|Antrim South||UUP||Danny Kinahan||Antrim West||DUP||7,413||Antrim (Northern Ireland)|
|Barrow and Furness||LAB||John Woodcock||Barrow and Furness||CON||1,128||Cumbria (North)|
|Berwick-upon-Tweed||CON||Anne-Marie Trevelyan||Berwick and Ashington||LAB||100||Northumberland (North)|
|Bolton West||CON||Chris Green||Bolton West||LAB||2,560||Western Manchester (Greater Manchester)|
|Brentford and Isleworth||LAB||Ruth Cadbury||Brentford and Chiswick||CON||5,442||Hounslow (South London)|
|Bridgend||LAB||Madeleine Moon||Bridgend and Vale of Glamorgan West||CON||1,757||Mid Glamorgan (Wales)|
|Brighton Pavilion||Green||Caroline Lucas||Brighton North||CON||127||East Sussex (South East)|
|Bury North||CON||David Nuttall||Bury||LAB||150||Western Manchester (Greater Manchester)|
|Cardiff North||CON||Craig Williams||Cardiff North||LAB||53||South Glamorgan (Wales)|
|Carshalton and Wallington||LIB||Tom Brake||Carshalton and Wallington||CON||416||Sutton (South London)|
|Chester, City of||LAB||Chris Matheson||Chester, City of||CON||733||Cheshire (Severn)|
|Clwyd South||LAB||Susan Elan Jones||Clwyd South and Montgomeryshire North||CON||3,785||Clwyd (Wales)|
|Coventry North West||LAB||Geoffrey Robinson||Coventry West and Meriden||CON||7,120||Coventry and Solihull (West Midlands)|
|Derby North||CON||Amanda Solloway||Derby North||LAB||9,150||Derbyshire (East Midlands)|
|Derby South||LAB||Margaret Beckett||Derby South||CON||3,217||Derbyshire (East Midlands)|
|Dumfriesshire, Clydesdale and Tweeddale||CON||David Mundell||Clydesdale and Eskdale||SNP||4,454||Ayrshire and Lanark (West Scotland)|
|Enfield North||LAB||Joan Ryan||Enfield||CON||1,121||Enfield (North London)|
|Fermanagh and South Tyrone||UUP||Tom Elliott||Fermanagh and South Tyrone||SF||2,971||Fermanagh (Northern Ireland)|
|Finchley and Golders Green||CON||Mike Freer||Finchley and Southgate||LAB||999||Barnet (North London)|
|Halesowen and Rowley Regis||CON||James Morris||Birmingham Selly Oak and Halesowen||LAB||1||Birmingham (West Midlands)|
|Hammersmith||LAB||Andy Slaughter||Hammersmith and Fulham||CON||7,564||Hammersmith and Fulham (North London)|
|Hampstead and Kilburn||LAB||Tulip Siddiq||Hampstead and Golders Green||CON||6,165||Camden (North London)|
|Harrow East||CON||Bob Blackman||Kenton||LAB||2,968||Harrow (North London)|
|Harrow West||LAB||Gareth Thomas||Harrow and Stanmore||CON||5,414||Harrow (North London)|
|Leeds North West||LIB||Greg Mulholland||Leeds North West||LAB||3,066||West Yorkshire (Yorkshire)|
|Londonderry East||DUP||Gregory Campbell||Glenshane||SF||3,163||Londonderry (Northern Ireland)|
|Morecambe and Lunesdale||CON||David Morris||Lancaster and Morecambe||LAB||1,423||Lancashire (Lancashire)|
|Morley and Outwood||CON||Andrea Jenkyns||Batley and Morley||LAB||4,848||West Yorkshire (Yorkshire)|
|Pudsey||CON||Stuart Andrew||Pudsey||LAB||7,415||West Yorkshire (Yorkshire)|
|Sheffield Hallam||LIB||Nick Clegg||Sheffield Hallam and Stocksbridge||LAB||3,710||South Yorkshire (Humberside)|
|Southampton Itchen||CON||Royston Smith||Southampton Itchen||LAB||298||Hampshire (South)|
|Southampton Test||LAB||Alan Whitehead||Southampton Test||CON||1,000||Hampshire (South)|
|Southport||LIB||John Pugh||Southport||CON||2,872||Merseyside (Lancashire)|
|Telford||CON||Lucy Allan||Telford||LAB||630||Shropshire (Severn)|
|Thanet South||CON||Craig Mackinlay||Thanet East||UKIP||753||Kent (South East)|
|Upper Bann||DUP||David Simpson||Upper Bann and Blackwater||SF||2,795||Armagh (Northern Ireland)|
|Vale of Clwyd||CON||James Davies||Flint and Rhuddlan||LAB||4,502||Clwyd (Wales)|
|Wirral West||LAB||Margaret Greenwood||Bebington and Heswall||CON||3,490||Merseyside (Lancashire)|
|Ynys Mon||LAB||Albert Owen||Ynys Mon and Arfon||PC||2,952||Gwynedd (Wales)|
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 nine fresh new seats:
|Bramhall and Poynton||CON||14,401||Eastern Manchester (Greater Manchester)|
|Down West||DUP||5,077||Armagh (Northern Ireland)|
|Falkirk||SNP||12,656||Central (East Scotland)|
|Forest Gate and Loxford||LAB||29,004||North London (North London)|
|Grimsby North and Barton||CON||5,417||Humber area (Humberside)|
|Isle of Wight West||CON||8,097||Hampshire (South)|
|Kinross-shire and Cowdenbeath||SNP||11,295||Fife (East Scotland)|
|Middlesbrough West and Stockton East||LAB||9,425||Teesside (North)|
|Peckham and Lewisham West||LAB||19,578||South London (South London)|
The Boundary Commission for England published initial proposals on 13 September 2016.
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 regional pages: North, Lancashire, Greater Manchester, Yorkshire, Humberside, West Midlands, East Midlands, Severn, East Anglia, Essex, West, North London, South London, South West, South, South East.
The Boundary Commission for Wales published initial proposals on 13 September 2016.
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 Regional page for more details.
The Boundary Commission for Scotland published its initial proposals on 20 October 2016.
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 East Scotland and West Scotland regional pages for more details.
New parliamentary boundaries were announced on 6 September by the Boundary Commission for Northern Ireland. Analysis of these initial proposals by Electoral Calculus indicates the the Ulster Unionist Party may lose both of its current Westminster seats, and that the republican Sinn Féin is likely to gain two seats, if voting patterns remain stable. The centre-left nationalist SDLP are also expected to lose one seat, as the total number of seats in the province decreases from 18 to 17.
The projected loss of the Ulster Unionist's MPs would be a heavy blow for the century-old party which has historically dominated Northern Ireland politics. Its influential past leaders include James Molyneux and David Trimble, who was the first-ever First Minister of Northern Ireland (1998-2002). Recently it has been eclipsed by the Democratic Unionist Party, founded by Ian Paisley in the 1970s, which is now the largest NI party at Westminster.
The UUP's two current seats are Antrim South, and Fermanagh and South Tyrone. The former is split and mostly becomes the new seat of 'Antrim West' which is predicted to be DUP. The latter seat, whose current UUP majority is only 530 votes, gains nationalist voters from Tyrone West, and is slated to become Sinn Féin's.
Other changes include the dismemberment into fragments of Belfast South (SDLP), and Ulster Mid (SF), which effectively disappear as seats. But Sinn Féin more than compensates for this by taking Upper Bann, and Londonderry East (renamed 'Glenshane') from the DUP. There is also one new seat created called Down West, which is predicted to be won by the DUP.
|Party||Old Seats||New Seats||Change||Commentary|
|DUP||8||8||0||Lose Londonderry East and Upper Bann;
gain Antrim West, and Down West (new seat)
Upper Bann and Blackwater,
Fermanagh and South Tyrone; lose Ulster Mid (disappears)
|SDLP||3||2||-1||Lose Belfast South (disappearing seat)|
|UUP||2||0||-2||Lose Antrim South, Fermanagh and South Tyrone|
|MIN||1||1||0||Hold Down North|
There has been interest in the likely effect of new boundaries which are likely to be brought in under this parliament. Electoral Calculus prepared a full set of notional implied results under the 600-seat "Sixth Periodic review" of boundaries which was conducted around 2013.
Although these boundaries were not used in 2015, they can still give a good approximation of the likely effect of the boundary changes. If we use the actual election result (adjusted slightly to compensate for model deficiencies) and feed it into the user-defined predictor, then we can see the effect of the boundaries.
Using these figures and the old boundaries gives CON 331, LAB 232, LIB 9, UKIP 1, Green 1, SNP 55, and Plaid 3, which is almost exactly correct. Then when we switch to the proposed 2018 boundaries we get
This gives the Conservatives a majority of 56 seats, well ahead of their current majority of 12. This is equivalent of nearly another twenty-two seats for the Conservatives.
The seat detail pages now have the new local election results, and updated local ward boundaries where they have changed. This major data upgrade shows clearly the interplay between recent national and local elections, as well as showing more details about the political make-up of each constituency.
You can see these new seat details by going to the index pages on the left-hand menu bar (England A-B, ..., Wales, Scotland, Northern Ireland), or by using the postcode lookup for any UK location:
An example seat is Arundel and South Downs (BN14 0TF) which has had updated boundaries.
Results include the following parties shown separately:
Local election results used are now:
Since 2010, sixty-two English councils have been given new boundaries by the Local Government Boundary Commission for England (LGBCE), and these new boundaries took effect at the 2015 elections. These new ward boundaries are now included for both the results drilldown and the accompanying maps.
In Northern Ireland, there has been a substantial redrawing of boundaries. There are now 11 district councils, with 462 wards which are grouped into 80 District Electoral Areas (DEAs). The NI local elections were conducted in 2014 using the DEAs, so Northern Ireland mapping and analysis is based on the DEAs rather than the actual wards. Please note that NI mapping data is difficult to obtain freely, so some boundaries may be slightly approximate.
It is expected that the Boundary Commissions will redraw parliamentary constituencies starting from Spring 2016 and using these 2015 local ward boundaries as their basic building blocks.
See also the information about the now-abandonned "Sixth Periodic review", to compare against the 2018 Review.