These are graphical representations of the House of Commons showing a comparison of party strengths as it was directly after the 2010 general election and before the 2015 general election:
| Constituency | Party of notional
incumbent before election | Member returned (2010) | Notes |
|---|
| Aberavon | | Labour | | (L) | |
| Aberconwy | | Labour | | (C) | Gain. MP for predecessor seat of Conwy, Betty Williams, did not stand. |
| Aberdeen North | | Labour | | (L) | |
| Aberdeen South | | Labour | | (L) | |
| Airdrie and Shotts | | Labour | | (L) | Previous incumbent John Reid did not stand. |
| Aldershot | | Conservative | | (C) | |
| Aldridge-Brownhills | | Conservative | | (C) | |
| Altrincham and Sale West | | Conservative | | (C) | |
| Alyn and Deeside | | Labour | | (L) | |
| Amber Valley | | Labour | | (C) | Gain. Defeated incumbent Judy Mallaber. |
| Angus | | SNP | | (SNP) | |
| Arfon | | Labour | | (PC) | MP for predecessor seat of Caernarfon. |
| Argyll and Bute | | Liberal Democrats | | (LD) | |
| Arundel and South Downs | | Conservative | | (C) | |
| Ashfield | | Labour | | (L) | Previous incumbent Geoff Hoon did not stand. |
| Ashford | | Conservative | | (C) | |
| Ashton-under-Lyne | | Labour | | (L) | |
| Aylesbury | | Conservative | | (C) | |
| Ayr, Carrick and Cumnock | | Labour | | (L) | |
| Banbury | | Conservative | | (C) | |
| Banff and Buchan | | SNP | | (SNP) | Previous incumbent Alex Salmond did not stand. |
| Barking | | Labour | | (L) | |
| Barnsley Central | | Labour | | (L) | Illsley was suspended from his party and had the whip withdrawn on 19 May after he was charged with false accounting over the United Kingdom Parliamentary expenses scandal.[4] By-election in 2011, see below. |
| Barnsley East | | Labour | | (L) | MP for predecessor seat of Barnsley East and Mexborough, Jeffrey Ennis, did not stand. |
| Barrow and Furness | | Labour | | (L Co-op) | Previous incumbent John Hutton did not stand. |
| Basildon and Billericay | | Conservative | | (C) | MP for predecessor seat of Billericay. |
| Basingstoke | | Conservative | | (C) | |
| Bassetlaw | | Labour | | (L) | |
| Bath | | Liberal Democrats | | (LD) | |
| Batley and Spen | | Labour | | (L) | |
| Battersea | | Labour | | (C) | Gain. Defeated incumbent Martin Linton. |
| Beaconsfield | | Conservative | | (C) | |
| Beckenham | | Conservative | | (C) | Previous incumbent Jacqui Lait did not stand. |
| Bedford | | Labour | | (C) | Gain. Defeated incumbent Patrick Hall. |
| Belfast East | | DUP | | (APNI) | Gain. Defeated incumbent Peter Robinson. |
| Belfast North | | DUP | | (DUP) | |
| Belfast South | | SDLP | | (SDLP) | |
| Belfast West | | Sinn Féin | | (SF) | By-election in 2011, see below. |
| Bermondsey and Old Southwark | | Liberal Democrats | | (LD) | MP for predecessor seat of North Southwark and Bermondsey. |
| Berwick-upon-Tweed | | Liberal Democrats | | data-sort-value="Beith, Alan" | Sir Alan Beith (LD) | |
| Berwickshire, Roxburgh and Selkirk | | Liberal Democrats | | (LD) | |
| Bethnal Green and Bow | | Respect | | (L) | Gain. Defeated incumbent George Galloway. |
| Beverley and Holderness | | Conservative | | (C) | |
| Bexhill and Battle | | Conservative | | (C) | |
| Bexleyheath and Crayford | | Conservative | | (C) | |
| Birkenhead | | Labour | | (L) | |
| Birmingham, Edgbaston | | Labour | | (L) | |
| Birmingham, Erdington | | Labour | | (L) | Previous incumbent Siôn Simon did not stand. |
| Birmingham, Hall Green | | Labour | | (L) | Reconfigured seat. Formerly MP for Birmingham Sparkbrook and Small Heath. MP for the old Birmingham Hall Green, Steve McCabe, won in its successor seat of Birmingham Selly Oak. |
| Birmingham, Hodge Hill | | Labour | | (L) | |
| Birmingham, Ladywood | | Labour | | (L) | Previous incumbent Clare Short stood down. |
| Birmingham, Northfield | | Labour | | (L) | |
| Birmingham, Perry Barr | | Labour | | (L) | |
| Birmingham, Selly Oak | | Labour | | (L) | Formerly MP for Birmingham Hall Green. Previous incumbent Lynne Jones did not stand. |
| Birmingham, Yardley | | Liberal Democrats | | (LD) | |
| Bishop Auckland | | Labour | | (L) | |
| Blackburn | | Labour | | (L) | |
| Blackley and Broughton | | Labour | | (L) | MP for predecessor seat of Manchester, Blackley. |
| Blackpool North and Cleveleys | | Labour | | (C) | MP for predecessor seat of Blackpool North and Fleetwood, Joan Humble, did not stand. |
| Blackpool South | | Labour | | (L) | |
| Blaenau Gwent | | BGPV | | (L) | Gain. Defeated incumbent Dai Davies elected at 2006 by-election. |
| Blaydon | | Labour | | (L) | |
| Blyth Valley | | Labour | | (L) | |
| Bognor Regis and Littlehampton | | Conservative | | (C) | |
| Bolsover | | Labour | | (L) | |
| Bolton North East | | Labour | | (L) | |
| Bolton South East | | Labour | | (L) | Previous incumbent Brian Iddon did not stand. |
| Bolton West | | Labour | | (L) | Previous incumbent Ruth Kelly did not stand. |
| Bootle | | Labour | | (L) | |
| Boston and Skegness | | Conservative | | (C) | |
| Bosworth | | Conservative | | (C) | |
| Bournemouth East | | Conservative | | (C) | |
| Bournemouth West | | Conservative | | (C) | Previous incumbent John Butterfill did not stand. |
| Bracknell | | Conservative | | (C) | Previous incumbent Andrew MacKay did not stand. |
| Bradford East | | Labour | | (LD) | Gain. Defeated Terry Rooney, MP for predecessor seat of Bradford North. |
| Bradford South | | Labour | | (L) | |
| Bradford West | | Labour | | (L) | By-election in 2012, see below. |
| Braintree | | Conservative | | (C) | |
| Brecon and Radnorshire | | Liberal Democrats | | (LD) | |
| Brent Central | | | | (LD) | Gain. Formerly MP for abolished seat of Brent East. Defeated Dawn Butler, MP for predecessor seat of Brent South. |
| Brent North | | Labour | | (L) | |
| Brentford and Isleworth | | Labour | | (C) | Gain. Defeated incumbent Ann Keen. |
| Brentwood and Ongar | | | | (C) | |
| Bridgend | | | | (L) | |
| Bridgwater and West Somerset | | Conservative | | (C) | MP for predecessor seat of Bridgwater. |
| Brigg and Goole | | Labour | | (C) | Gain. Defeated incumbent Ian Cawsey. |
| Brighton, Kemptown | | Labour | | (C) | Gain. Previous incumbent Des Turner did not stand. |
| Brighton, Pavilion | | | | (G) | Gain. Previous incumbent David Lepper did not stand. First Green MP elected. |
| Bristol East | | | | (L) | |
| Bristol North West | | Labour | | (C) | Gain. Previous incumbent Doug Naysmith did not stand. |
| Bristol South | | Labour | | (L) | |
| Bristol West | | Liberal Democrats | | (LD) | |
| Broadland | | Conservative | | (C) | MP for predecessor seat of Mid Norfolk. |
| Bromley and Chislehurst | | Conservative | | (C) | Elected at 2006 by-election. |
| Bromsgrove | | Conservative | | (C) | Previous incumbent Julie Kirkbride did not stand. |
| Broxbourne | | Conservative | | (C) | |
| Broxtowe | | Labour | | (C) | Gain. Defeated incumbent Nick Palmer. |
| Buckingham | | Conservative | | (Speaker) | Seat held. Previously elected as a Conservative. |
| Burnley | | Labour | | (LD) | Gain. Previous incumbent Kitty Ussher did not stand. |
| Burton | | Labour | | (C) | Gain. Previous incumbent Janet Dean did not stand. |
| Bury North | | Labour | | (C) | Gain. Previous incumbent David Chaytor did not stand. |
| Bury South | | Labour | | (L) | |
| Bury St Edmunds | | Conservative | | (C) | |
| Caerphilly | | Labour | | (L) | |
| Caithness, Sutherland and Easter Ross | | Liberal Democrats | | (LD) | |
| Calder Valley | | Labour | | (C) | Gain. Previous incumbent Christine McCafferty did not stand. |
| Camberwell and Peckham | | Labour | | (L) | |
| Camborne and Redruth | | Liberal Democrats | | (C) | Gain. Defeated Julia Goldsworthy, MP for predecessor seat of Falmouth and Camborne. |
| Cambridge | | Liberal Democrats | | (LD) | Previous incumbent David Howarth did not stand. |
| Cannock Chase | | Labour | | (C) | Gain. Previous incumbent Tony Wright did not stand. |
| Canterbury | | Conservative | | (C) | |
| Cardiff Central | | Liberal Democrats | | (LD) | |
| Cardiff North | | Labour | | (C) | Gain. Defeated incumbent Julie Morgan. |
| Cardiff South and Penarth | | Labour | | (L Co-op) | By-election in 2012, see below. |
| Cardiff West | | Labour | | (L) | |
| Carlisle | | Labour | | (C) | Gain. Previous incumbent Eric Martlew did not stand. |
| Carmarthen East and Dinefwr | | Plaid Cymru | | (PC) | Previous incumbent Adam Price did not stand. |
| Carmarthen West and South Pembrokeshire | | Labour | | (C) | Gain. Defeated incumbent Nick Ainger. |
| Carshalton and Wallington | | Liberal Democrats | | (LD) | |
| Castle Point | | Conservative | | (C) | Defeated Bob Spink, previous incumbent who ran as an independent. He was elected as a Conservative but defected to UKIP and then sat as an independent. |
| Central Ayrshire | | Labour | | (L) | |
| Central Devon | | Conservative | | (C) | New constituency. |
| Central Suffolk and North Ipswich | | Conservative | | (C) | Previous incumbent Michael Lord did not stand. |
| Ceredigion | | Liberal Democrats | | (LD) | |
| Charnwood | | Conservative | | (C) | |
| Chatham and Aylesford | | Labour | | (C) | Gain. Defeated incumbent Jonathan Shaw. |
| Cheadle | | Liberal Democrats | | (LD) | Elected at 2005 by-election. |
| Chelmsford | | Conservative | | (C) | MP for predecessor seat of West Chelmsford. |
| Chelsea and Fulham | | Conservative | | (C) | New constituency. Formerly MP for Hammersmith and Fulham. |
| Cheltenham | | Liberal Democrats | | (LD) | |
| Chesham and Amersham | | Conservative | | (C) | |
| City of Chester | | Labour | | (C) | Gain. Defeated incumbent Christine Russell. |
| Chesterfield | | Liberal Democrats | | (L) | Gain. Defeated incumbent Paul Holmes. |
| Chichester | | Conservative | | (C) | |
| Chingford and Woodford Green | | Conservative | | (C) | |
| Chippenham | | Liberal Democrats | | (LD) | New constituency. |
| Chipping Barnet | | Conservative | | (C) | |
| Chorley | | Labour | | (L) | |
| Christchurch | | Conservative | | (C) | |
| Cities of London and Westminster | | Conservative | | (C) | |
| Clacton | | Conservative | | (C) | MP for predecessor seat of Harwich. Douglas Carswell defected to UKIP in 2014, resigned his seat and was then elected as UKIP's first ever MP at the by-election held after he defected, see below. |
| Cleethorpes | | Labour | | (C) | Gain. Defeated Incumbent Shona McIsaac. |
| Clwyd South | | Labour | | (L) | Previous incumbent Martyn Jones did not stand. |
| Clwyd West | | Conservative | | (C) | |
| Coatbridge, Chryston and Bellshill | | Labour | | (L) | |
| Colchester | | Liberal Democrats | | (LD) | |
| Colne Valley | | Labour | | (C) | Gain. Previous incumbent Kali Mountford did not stand. |
| Congleton | | Conservative | | (C) | Previous incumbent Ann Winterton did not stand. |
| Copeland | | Labour | | (L) | |
| Corby | | Labour | | (C) | Gain. Defeated incumbent Phil Hope. Louise Mensch since marriage in June 2011. By-election in 2012, see below. |
| The Cotswolds | | Conservative | | (C) | MP for predecessor seat of Cotswold. |
| Coventry North East | | Labour | | (L) | |
| Coventry North West | | Labour | | (L) | |
| Coventry South | | Labour Party | | (L) | |
| Crawley | | Labour | | (C) | Gain. Previous incumbent Laura Moffatt did not stand. |
| Crewe and Nantwich | | Labour | | (C) | Seat held. Won by the Conservatives at 2008 by-election. |
| Croydon Central | | Labour | | (C) | Seat held. Notional gain following boundary changes. |
| Croydon North | | Labour | | (L) | By-election in 2012 after death of MP, see below. |
| Croydon South | | Conservative | | (C) | |
| Cumbernauld, Kilsyth and Kirkintilloch East | | Labour | | (L) | Previous incumbent Rosemary McKenna did not stand. |
| Cynon Valley | | Labour | | (L) | |
| Dagenham and Rainham | | Labour | | (L) | MP for predecessor seat of Dagenham. |
| Darlington | | Labour | | (L) | Previous incumbent Alan Milburn did not stand. |
| Dartford | | Labour | | (C) | Gain. Previous incumbent Howard Stoate did not stand. |
| Daventry | | Conservative | | (C) | Previous incumbent Tim Boswell did not stand. |
| Delyn | | Labour | | (L) | |
| Denton and Reddish | | Labour | | (L) | |
| Derby North | | Labour | | (L) | Previous incumbent Bob Laxton did not stand. |
| Derby South | | Labour | | (L) | |
| Derbyshire Dales | | Conservative | | (C) | MP for predecessor seat of West Derbyshire. |
| Devizes | | Conservative | | (C) | Previous incumbent Michael Ancram did not stand. |
| Dewsbury | | Labour | | (C) | Gain. Defeated incumbent Shahid Malik. |
| Don Valley | | Labour | | (L) | |
| Doncaster Central | | Labour | | (L) | |
| Doncaster North | | Labour | | (L) | |
| Dover | | Labour | | (C) | Gain. Defeated incumbent Gwyn Prosser. |
| Dudley North | | Labour | | (L) | |
| Dudley South | | Labour | | (C) | Gain. Previous incumbent Ian Pearson did not stand. |
| Dulwich and West Norwood | | Labour | | (L) | |
| Dumfries and Galloway | | Labour | | (L) | |
| Dumfriesshire, Clydesdale and Tweeddale | | Conservative | | (C) | |
| Dundee East | | SNP | | (SNP) | |
| Dundee West | | Labour | | (L) | |
| Dunfermline and West Fife | | Labour | | (L) | Notional hold. Defeated incumbent Willie Rennie who won seat for the Liberal Democrats at 2006 by-election. |
| City of Durham | | Labour | | (L) | |
| Dwyfor Meirionnydd | | Plaid Cymru | | (PC) | MP for predecessor seat of Meirionnydd Nant Conwy. |
| Ealing Central and Acton | | Labour | | (C) | Gain. MP for predecessor seat of Ealing, Acton and Shepherd's Bush, Andy Slaughter won in Hammersmith. |
| Ealing North | | Labour | | (L) | 1st time since 1974 that the party with the largest number of seats has not won the seat. |
| Ealing, Southall | | Labour | | (L) | Elected at 2007 by-election. |
| Easington | | Labour | | (L) | Previous incumbent John Cummings did not stand. |
| East Antrim | | DUP | | (DUP) | |
| East Devon | | Conservative | | (C) | |
| East Dunbartonshire | | Liberal Democrats | | (LD) | |
| East Ham | | Labour | | (L) | |
| East Hampshire | | Conservative | | (C) | Previous incumbent Michael Mates did not stand. |
| East Kilbride, Strathaven and Lesmahagow | | Labour | | (L) | Previous incumbent Adam Ingram did not stand. |
| East Londonderry | | DUP | | (DUP) | |
| East Lothian | | Labour | | (L) | Previous incumbent Anne Picking did not stand. |
| East Renfrewshire | | | | (L) | |
| East Surrey | | Conservative | | (C) | Previous incumbent Peter Ainsworth did not stand. |
| East Worthing and Shoreham | | Conservative | | (C) | |
| East Yorkshire | | Conservative | | (C) | |
| Eastbourne | | Conservative | | (LD) | Gain. Defeated incumbent Nigel Waterson. |
| Eastleigh | | Liberal Democrats | | (LD) | Chris Huhne resigned 2013. By-election in 2013, see below. |
| Eddisbury | | | | (C) | |
| Edinburgh East | | Labour | | (L) | Previous incumbent Gavin Strang did not stand. |
| Edinburgh North and Leith | | | | (L Co-op) | |
| Edinburgh South | | Labour | | (L) | Previous incumbent Nigel Griffiths did not stand. |
| Edinburgh South West | | Labour | | (L) | |
| Edinburgh West | | Liberal Democrats | | (LD) | Previous incumbent John Barrett did not stand. |
| Edmonton | | | | (L Co-op) | |
| Ellesmere Port and Neston | | | | (L) | |
| Elmet and Rothwell | | | | (C) | Gain. MP for predecessor seat of Elmet, Colin Burgon, did not stand. |
| Eltham | | | | (L) | |
| Enfield North | | Labour | | (C) | Gain. Defeated incumbent Joan Ryan. |
| Enfield, Southgate | | Conservative | | (C) | |
| Epping Forest | | | | (C) | |
| Epsom and Ewell | | Conservative | | (C) | |
| Erewash | | Labour | | (C) | Gain. Previous incumbent Liz Blackman did not stand. |
| Erith and Thamesmead | | | | (L) | Previous incumbent John Austin did not stand. |
| Esher and Walton | | Conservative | | (C) | Previous incumbent Ian Taylor did not stand. |
| Exeter | | Labour | | (L) | |
| Falkirk | | Labour | | (L) | Suspended then resigned from his party in 2012.[5] |
| Fareham | | Conservative | | (C) | |
| Faversham and Mid Kent | | Conservative | | (C) | |
| Feltham and Heston | | Labour | | (L Co-op) | By-election on MP's death in 2011, see below. |
| Fermanagh and South Tyrone | | Sinn Féin | | (SF) | |
| Filton and Bradley Stoke | | Conservative | | (C) | New constituency. |
| Finchley and Golders Green | | Conservative | | (C) | Notional hold following boundary changes. Previous incumbent Rudi Vis did not stand. |
| Folkestone and Hythe | | Conservative | | (C) | Previous incumbent Michael Howard did not stand. |
| Forest of Dean | | Conservative | | (C) | |
| Foyle | | SDLP | | (SDLP) | |
| Fylde | | Conservative | | (C) | Previous incumbent Michael Jack did not stand. |
| Gainsborough | | Conservative | | (C) | |
| Garston and Halewood | | Labour | | (L) | MP for predecessor seat of Liverpool Garston. |
| Gateshead | | Labour | | (L) | MP for predecessor seat of Tyne Bridge, David Clelland, did not stand. |
| Gedling | | Labour | | (L) | |
| Gillingham and Rainham | | Labour | | (C) | Gain. Defeated Paul Clark, MP for predecessor seat of Gillingham. |
| Glasgow Central | | Labour | | (L) | Previous incumbent Mohammad Sarwar did not stand. |
| Glasgow East | | Labour | | (L) | Notional hold. Defeated incumbent John Mason who won seat for the SNP at 2008 by-election. |
| Glasgow North | | Labour | | (L) | |
| Glasgow North East | | Labour | | (L) | Elected at 2009 by-election. |
| Glasgow North West | | Labour | | (L) | |
| Glasgow South | | Labour | | (L) | |
| Glasgow South West | | Labour | | (L Co-op) | |
| Glenrothes | | Labour | | (L) | Elected at 2008 by-election. |
| Gloucester | | Labour | | (C) | Gain. Defeated incumbent Parmjit Dhanda. |
| Gordon | | Liberal Democrats | | (LD) | |
| Gosport | | Conservative | | (C) | Previous incumbent Peter Viggers did not stand. |
| Gower | | Labour | | (L) | |
| Grantham and Stamford | | Conservative | | (C) | Previous incumbent Quentin Davies did not stand. |
| Gravesham | | Conservative | | (C) | |
| Great Grimsby | | Labour | | (L) | |
| Great Yarmouth | | Labour | | (C) | Gain. Defeated incumbent Tony Wright. |
| Greenwich and Woolwich | | Labour | | (L) | |
| Guildford | | Conservative | | (C) | |
| Hackney North and Stoke Newington | | Labour | | (L) | |
| Hackney South and Shoreditch | | Labour | | (L Co-op) | |
| Halesowen and Rowley Regis | | Labour | | (C) | Gain. Previous incumbent Sylvia Heal did not stand. |
| Halifax | | Labour | | (L Co-op) | |
| Haltemprice and Howden | | Conservative | | (C) | |
| Halton | | Labour | | (L) | |
| Hammersmith | | Labour | | (L) | Notional hold following boundary changes. Formerly MP for Ealing, Acton and Shepherd's Bush. Greg Hands, MP for predecessor seat of Hammersmith and Fulham, won in Chelsea and Fulham. |
| Hampstead and Kilburn | | Labour | | (L) | MP for predecessor seat of Hampstead and Highgate. |
| Harborough | | Conservative | | (C) | |
| Harlow | | Labour | | (C) | Gain. Defeated incumbent Bill Rammell. |
| Harrogate and Knaresborough | | Liberal Democrats | | (C) | Gain. Previous incumbent Phil Willis did not stand. |
| Harrow East | | Labour | | (C) | Gain. Defeated incumbent Tony McNulty. |
| Harrow West | | Labour | | (L Co-op) | |
| Hartlepool | | Labour | | (L) | |
| Harwich and North Essex | | Conservative | | (C) | MP for predecessor seat of North Essex. |
| Hastings and Rye | | Labour | | (C) | Gain. Defeated incumbent Michael Foster. |
| Havant | | Conservative | | (C) | |
| Hayes and Harlington | | Labour | | (L) | |
| Hazel Grove | | Liberal Democrats | | (LD) | |
| Hemel Hempstead | | Conservative | | (C) | |
| Hemsworth | | Labour | | (L) | |
| Hendon | | Labour | | (C) | Gain. Defeated incumbent Andrew Dismore. |
| Henley | | Conservative | | (C) | Elected at 2008 by-election. |
| Hereford and South Herefordshire | | Liberal Democrats | | (C) | Gain. MP for predecessor seat of Hereford, Paul Keetch, did not stand. |
| Hertford and Stortford | | Conservative | | (C) | |
| Hertsmere | | Conservative | | (C) | |
| Hexham | | Conservative | | (C) | Previous incumbent Peter Atkinson did not stand. |
| Heywood and Middleton | | Labour | | (L Co-op) | |
| High Peak | | Labour | | (C) | Gain. Defeated incumbent Tom Levitt. |
| Hitchin and Harpenden | | Conservative | | (C) | |
| Holborn and St Pancras | | Labour | | (L) | |
| Hornchurch and Upminster | | Conservative | | (C) | MP for predecessor seat of Upminster. |
| Hornsey and Wood Green | | Liberal Democrats | | (LD) | |
| Horsham | | Conservative | | (C) | |
| Houghton and Sunderland South | | Labour | | (L) | MP for predecessor seat of Houghton and Washington East, Fraser Kemp, did not stand. |
| Hove | | Labour | | (C) | Gain. Defeated incumbent Celia Barlow. |
| Huddersfield | | Labour | | (L Co-op) | |
| Huntingdon | | Conservative | | (C) | |
| Hyndburn | | Labour | | (L) | Previous incumbent Greg Pope did not stand. |
| Ilford North | | Conservative | | (C) | |
| Ilford South | | Labour | | (L Co-op) | |
| Inverclyde | | Labour | | (L) | By-election on MP's death in 2013, see below. |
| | Liberal Democrats | | (LD) | |
| Ipswich | | Labour | | (C) | Gain. Defeated incumbent Chris Mole. |
| Isle of Wight | | Conservative | | (C) | |
| Islington North | | Labour | | (L) | |
| Islington South and Finsbury | | Labour | | (L) | |
| Islwyn | | Labour | | (L Co-op) | Previous incumbent Don Touhig did not stand. |
| Jarrow | | Labour | | (L) | |
| Keighley | | Labour | | (C) | Gain. Previous incumbent Ann Cryer did not stand. |
| Kenilworth and Southam | | Conservative | | (C) | New constituency. Formerly MP for Rugby and Kenilworth. |
| Kensington | | Conservative | | data-sort-value="Rifkind, Malcolm" | Sir Malcolm Rifkind (C) | MP for predecessor seat of Kensington and Chelsea. |
| Kettering | | Conservative | | (C) | |
| Kilmarnock and Loudoun | | Labour | | (L Co-op) | Previous incumbent Des Browne did not stand. |
| Kingston and Surbiton | | Liberal Democrats | | (LD) | |
| Kingston upon Hull East | | Labour | | (L) | Previous incumbent John Prescott did not stand. |
| Kingston upon Hull North | | Labour | | (L) | |
| Kingston upon Hull West and Hessle | | Labour | | (L) | |
| Kingswood | | Labour | | (C) | Gain. Defeated incumbent Roger Berry. |
| Kirkcaldy and Cowdenbeath | | Labour | | (L) | Outgoing Prime Minister (resigned as PM 11 May 2010). |
| Knowsley | | Labour | | (L) | Formerly MP for abolished seat of Knowsley North and Sefton East. MP for predecessor seat of Knowsley South, Eddie O'Hara, did not stand. |
| Lagan Valley | | DUP | | (DUP) | |
| Lanark and Hamilton East | | Labour | | (L) | |
| Lancaster and Fleetwood | | Labour | | (C) | Notional gain. MP for predecessor seat of Lancaster and Wyre, Ben Wallace won in Wyre and Preston North. |
| Leeds Central | | Labour | | (L) | |
| Leeds East | | Labour | | (L) | |
| Leeds North East | | Labour | | (L) | |
| Leeds North West | | Liberal Democrats | | (LD) | |
| Leeds West | | Labour | | (L) | Previous incumbent John Battle did not stand. |
| Leicester East | | Labour | | (L) | |
| Leicester South | | Labour | | (L) | |
| Leicester West | | Labour | | (L) | Previous incumbent Patricia Hewitt did not stand. |
| Leigh | | Labour | | (L) | |
| Lewes | | Liberal Democrats | | (LD) | |
| Lewisham East | | Labour | | (L) | Previous incumbent Bridget Prentice did not stand. |
| Lewisham West and Penge | | Labour | | (L) | MP for predecessor seat of Lewisham West |
| Lewisham, Deptford | | Labour | | (L) | |
| Leyton and Wanstead | | Labour | | (L) | Previous incumbent Harry Cohen did not stand. |
| Lichfield | | Conservative | | (C) | |
| Lincoln | | Labour | | (C) | Gain. Defeated incumbent Gillian Merron. |
| Linlithgow and East Falkirk | | Labour | | (L) | |
| Liverpool, Riverside | | Labour | | (L Co-op) | |
| Liverpool, Walton | | Labour | | (L) | Previous incumbent Peter Kilfoyle did not stand. |
| Liverpool, Wavertree | | Labour | | (L Co-op) | Previous incumbent Jane Kennedy did not stand. |
| Liverpool, West Derby | | Labour | | (L Co-op) | Previous incumbent Bob Wareing did not stand. |
| Livingston | | Labour | | (L) | Previous incumbent Jim Devine, elected at 2005 by-election, did not stand. |
| Llanelli | | Labour | | (L) | |
| Loughborough | | Labour | | (C) | Gain. Defeated incumbent Andy Reed. |
| Louth and Horncastle | | Conservative | | data-sort-value="Tapsell, Peter" | Sir Peter Tapsell (C) | |
| Ludlow | | Conservative | | (C) | |
| Luton North | | Labour | | (L) | |
| Luton South | | Labour | | (L Co-op) | Previous incumbent Margaret Moran did not stand. |
| Macclesfield | | Conservative | | (C) | Previous incumbent Nicholas Winterton did not stand. |
| Maidenhead | | Conservative | | (C) | |
| Maidstone and The Weald | | Conservative | | (C) | Previous incumbent Ann Widdecombe did not stand. |
| Makerfield | | Labour | | (L) | Previous incumbent Ian McCartney did not stand. |
| Maldon | | Conservative | | (C) | MP for predecessor seat of Maldon and East Chelmsford. |
| Manchester Central | | Labour | | Tony Lloyd (L) | By-election in 2012, see below. |
| Manchester, Gorton | | Labour | | data-sort-value="Kaufman, Gerald" | Sir Gerald Kaufman (L) | |
| Manchester Withington | | Liberal Democrats | | (LD) | |
| Mansfield | | Labour | | (L) | |
| Meon Valley | | Conservative | | (C) | New constituency. |
| Meriden | | Conservative | | (C) | |
| Merthyr Tydfil and Rhymney | | Labour | | (L) | |
| Mid Bedfordshire | | Conservative | | (C) | |
| Mid Derbyshire | | | | (C) | New constituency. |
| Mid Dorset and North Poole | | Liberal Democrats | | (LD) | |
| Mid Norfolk | | Conservative | | (C) | Reconfigured seat. MP for the old Mid Norfolk seat, Keith Simpson, won in its successor seat of Broadland. |
| Mid Sussex | | Conservative | | (C) | |
| Mid Ulster | | Sinn Féin | | (SF) | |
| Mid Worcestershire | | Conservative | | (C) | |
| Middlesbrough | | Labour | | data-sort-value="Bell, Stuart" | Sir Stuart Bell (L) | |
| Middlesbrough South and East Cleveland | | Labour | | (L) | Seat vacant due to death of previous incumbent Ashok Kumar. |
| Midlothian | | Labour | | (L) | |
| Milton Keynes North | | Labour | | (C) | Notional gain following boundary changes. MP for predecessor seat of North East Milton Keynes. |
| Milton Keynes South | | Labour | | (C) | Gain. Defeated Phyllis Starkey, MP for predecessor seat of Milton Keynes South West. |
| Mitcham and Morden | | Labour | | (L) | |
| Mole Valley | | Conservative | | data-sort-value="Beresford, Paul" | Sir Paul Beresford (C) | |
| Monmouth | | Conservative | | (C) | |
| Montgomeryshire | | Liberal Democrats | | (C) | Gain. Defeated incumbent Lembit Öpik. |
| Moray | | SNP | | (SNP) | |
| Morecambe and Lunesdale | | Labour | | (C) | Gain. Defeated incumbent Geraldine Smith. |
| Morley and Outwood | | Labour | | (L Co-op) | Formerly MP for the abolished seat of Normanton. MP for the predecessor seat of Morley and Rothwell, Colin Challen, did not stand. |
| Motherwell and Wishaw | | Labour | | (L) | |
| Na h-Eileanan an Iar (Western Isles) | | SNP | | (SNP) | |
| Neath | | Labour | | (L) | |
| New Forest East | | Conservative | | (C) | |
| New Forest West | | Conservative | | (C) | |
| Newark | | Conservative | | (C) | |
| Newbury | | Conservative | | (C) | |
| Newcastle upon Tyne Central | | Labour | | (L) | Previous incumbent Jim Cousins did not stand. |
| Newcastle upon Tyne East | | Labour | | (L) | MP for predecessor seat of Newcastle upon Tyne East and Wallsend. |
| Newcastle upon Tyne North | | Labour | | (L) | Previous incumbent Doug Henderson did not stand. |
| Newcastle-under-Lyme | | Labour | | (L) | |
| Newport East | | Labour | | (L) | |
| | Labour | | (L) | |
| Newry and Armagh | | Sinn Féin | | (SF) | |
| Newton Abbot | | Liberal Democrats | | (C) | Gain. Defeated Richard Younger-Ross, MP for predecessor seat of Teignbridge. |
| Normanton, Pontefract and Castleford | | Labour | | (L) | MP for predecessor seat of Pontefract and Castleford. |
| North Antrim | | DUP | | (DUP) | Previous incumbent Ian Paisley, Sr. did not stand. |
| North Ayrshire and Arran | | Labour | | (L) | |
| North Cornwall | | Liberal Democrats | | (LD) | |
| North Devon | | Liberal Democrats | | (LD) | |
| North Dorset | | Conservative | | (C) | |
| North Down | | UUP | | data-sort-value="Hermon, Sylvia" | Sylvia, Lady Hermon (Ind) | Seat held. Stood as Independent Unionist in objection to party line. |
| North Durham | | Labour | | (L) | |
| North East Bedfordshire | | Conservative | | (C) | |
| North East Cambridgeshire | | Conservative | | (C) | Previous incumbent Malcolm Moss did not stand. |
| North East Derbyshire | | Labour | | (L) | |
| North East Fife | | Liberal Democrats | | data-sort-value="Campbell, Menzies" | Sir Menzies Campbell (LD) | |
| North East Hampshire | | Conservative | | (C) | |
| North East Hertfordshire | | Conservative | | (C) | |
| North East Somerset | | Conservative | | (C) | Notional hold following boundary changes. Defeated Dan Norris, MP for predecessor seat of Wansdyke. |
| North Herefordshire | | Conservative | | (C) | MP for predecessor seat of Leominster. |
| North Norfolk | | Liberal Democrats | | (LD) | |
| North Shropshire | | Conservative | | (C) | |
| North Somerset | | Conservative | | (C) | MP for predecessor seat of Woodspring. |
| North Swindon | | Labour | | (C) | Gain. Previous incumbent Michael Wills did not stand. |
| North Thanet | | Conservative | | (C) | |
| North Tyneside | | Labour | | (L) | Previous incumbent Stephen Byers did not stand. |
| North Warwickshire | | Labour | | (C) | Gain. Defeated incumbent Mike O’Brien. |
| North West Cambridgeshire | | Conservative | | (C) | |
| North West Durham | | Labour | | (L) | Previous incumbent Hilary Armstrong did not stand. |
| North West Hampshire | | Conservative | | data-sort-value="Young, George" | Sir George Young, Bt (C) | |
| North West Leicestershire | | Labour | | (C) | Gain. Previous incumbent David Taylor did not stand. |
| North West Norfolk | | | | (C) | |
| North Wiltshire | | Conservative | | (C) | |
| Northampton North | | Labour | | (C) | Gain. Defeated incumbent Sally Keeble. |
| Northampton South | | Labour | | (C) | Seat held. Notional gain following boundary changes. |
| Norwich North | | Conservative | | (C) | Notional hold following boundary changes. Seat gained from Labour under old boundaries at 2009 by-election. |
| | Labour | | (LD) | Gain. Defeated incumbent Charles Clarke. |
| Nottingham East | | Labour | | (L Co-op) | Previous incumbent John Heppell did not stand. |
| Nottingham North | | Labour | | Graham Allen (L) | |
| Nottingham South | | Labour | | (L) | Previous incumbent Alan Simpson did not stand. |
| Nuneaton | | Labour | | (C) | Gain. Previous incumbent Bill Olner did not stand. |
| Ochil and South Perthshire | | Labour | | (L) | |
| Ogmore | | Labour | | (L) | |
| Old Bexley and Sidcup | | Conservative | | (C) | Formerly MP for the abolished seat of Hornchurch. |
| Oldham East and Saddleworth | | Labour | | (L) | On 5 November 2010, election declared void on petition causing a by-election. |
| Oldham West and Royton | | Labour | | (L) | |
| Orkney and Shetland | | Liberal Democrats | | (LD) | |
| Orpington | | Conservative | | (C) | Previous incumbent John Horam did not stand. |
| Oxford East | | Labour | | (L) | |
| Oxford West and Abingdon | | Liberal Democrats | | (C) | Gain. Defeated incumbent Evan Harris. |
| | Labour | | (L) | |
| | Labour | | (L) | |
| Pendle | | Labour | | (C) | Gain. Defeated incumbent Gordon Prentice. |
| Penistone and Stocksbridge | | Labour | | (L) | MP for predecessor seat of Sheffield Hillsborough. |
| Penrith and The Border | | Conservative | | (C) | Previous incumbent David Maclean did not stand. |
| Perth and North Perthshire | | SNP | | (SNP) | |
| Peterborough | | Conservative | | (C) | |
| Plymouth, Moor View | | Labour | | (L) | MP for the predecessor seat of Plymouth Devonport. |
| Plymouth, Sutton and Devonport | | Labour | | (C) | Gain. Defeated Linda Gilroy, MP for predecessor seat of Plymouth Sutton. |
| Pontypridd | | Labour | | (L) | Previous incumbent Kim Howells did not stand. |
| Poole | | Conservative | | (C) | |
| Poplar and Limehouse | | Labour | | (L) | MP for predecessor seat of Poplar and Canning Town. |
| Portsmouth North | | Labour | | (C) | Gain. Defeated incumbent Sarah McCarthy-Fry. |
| Portsmouth South | | Liberal Democrats | | (LD) | |
| Preseli Pembrokeshire | | Conservative | | (C) | |
| Preston | | Labour | | (L Co-op) | |
| Pudsey | | Labour | | (C) | Gain. Previous incumbent Paul Truswell did not stand. |
| Putney | | Conservative | | (C) | |
| Rayleigh and Wickford | | Conservative | | (C) | MP for predecessor seat of Rayleigh. |
| Reading East | | Conservative | | (C) | |
| Reading West | | Labour | | (C) | Gain. Previous incumbent Martin Salter did not stand. |
| Redcar | | Labour | | (LD) | Gain. Defeated incumbent Vera Baird. |
| Redditch | | Labour | | (C) | Gain. Defeated incumbent Jacqui Smith. |
| Reigate | | Conservative | | (C) | |
| Rhondda | | Labour | | (L) | |
| Ribble Valley | | Conservative | | (C) | |
| Richmond (Yorks) | | Conservative | | (C) | |
| Richmond Park | | | | (C) | Gain. Defeated incumbent Susan Kramer. |
| Rochdale | | | (L) | Gain. Defeated incumbent Paul Rowen. |
| Rochester and Strood | | Conservative | | (C) | Notional hold following boundary changes. MP for predecessor seat of Medway, Bob Marshall-Andrews, did not stand. Mark Reckless defected to UKIP, resigned his seat and was then elected as the second UKIP Member at the by-election triggered by his resignation. |
| Rochford and Southend East | | Conservative | | (C) | |
| Romford | | Conservative | | (C) | |
| Romsey and Southampton North | | Liberal Democrats | | (C) | Gain. Defeated Sandra Gidley, MP for predecessor seat of Romsey. |
| Ross, Skye and Lochaber | | Liberal Democrats | | (LD) | |
| Rossendale and Darwen | | Labour | | (C) | Gain. Defeated incumbent Janet Anderson. |
| Rother Valley | | Labour | | (L) | |
| Rotherham | | Labour | | (L) | By-election held in 2012, see below. |
| Rugby | | Labour | | (C) | Notional gain following boundary changes. MP for predecessor seat of Rugby and Kenilworth, Jeremy Wright, won in Kenilworth and Southam. |
| Ruislip, Northwood and Pinner | | Conservative | | (C) | MP for predecessor seat of Ruislip-Northwood. |
| Runnymede and Weybridge | | Conservative | | (C) | |
| Rushcliffe | | Conservative | | (C) | |
| Rutherglen and Hamilton West | | Labour | | (L Co-op) | Previous incumbent Tommy McAvoy did not stand. |
| Rutland and Melton | | Conservative | | (C) | |
| Saffron Walden | | Conservative | | data-sort-value="Haselhurst, Alan" | Sir Alan Haselhurst (C) | |
| Salford and Eccles | | Labour | | (L) | MP for predecessor seat of Salford. |
| Salisbury | | Conservative | | (C) | Previous incumbent Robert Key did not stand. |
| Scarborough and Whitby | | Conservative | | (C) | |
| Scunthorpe | | Labour | | (L) | Previous incumbent Elliot Morley did not stand. |
| Sedgefield | | Labour | | (L) | Elected at 2007 by-election. |
| Sefton Central | | Labour | | (L) | MP for predecessor seat of Crosby, Claire Curtis-Thomas, did not stand. |
| Selby and Ainsty | | Conservative | | (C) | Notional hold following boundary changes. MP for predecessor seat of Selby, John Grogan, did not stand. |
| Sevenoaks | | Conservative | | (C) | |
| Sheffield Central | | Labour | | (L) | Previous incumbent Richard Caborn did not stand. |
| Sheffield South East | | Labour | | (L) | MP for predecessor seat of Sheffield Attercliffe. |
| Sheffield, Brightside and Hillsborough | | Labour | | (L) | MP for predecessor seat of Sheffield Brightside. |
| Sheffield, Hallam | | Liberal Democrats | | (LD) | Party leader; Appointed Deputy Prime Minister on 12 May |
| Sheffield, Heeley | | Labour | | (L Co-op) | |
| Sherwood | | Labour | | (C) | Gain. Previous incumbent Paddy Tipping did not stand. |
| Shipley | | Conservative | | (C) | |
| Shrewsbury and Atcham | | Conservative | | (C) | |
| Sittingbourne and Sheppey | | Conservative | | (C) | Gain. Notional hold following boundary changes. Previous incumbent Derek Wyatt did not stand. |
| Skipton and Ripon | | Conservative | | (C) | Previous incumbent David Curry did not stand. |
| Sleaford and North Hykeham | | Conservative | | (C) | Previous incumbent Douglas Hogg did not stand. |
| Slough | | Labour | | (L) | |
| Solihull | | Conservative | | (LD) | Seat held. Notional gain following boundary changes. |
| Somerton and Frome | | Liberal Democrats | | (LD) | |
| South Antrim | | Democratic Unionist Party | | (DUP) | |
| South Basildon and East Thurrock | | Labour | | (C) | Gain. Defeated Angela Smith, MP for predecessor seat of Basildon. |
| South Cambridgeshire | | | | (C) | |
| South Derbyshire | | Labour | | (C) | Gain. Previous incumbent Mark Todd did not stand. |
| South Dorset | | Labour | | (C) | Gain. Defeated incumbent Jim Knight. |
| South Down | | SDLP | | (SDLP) | Previous incumbent Eddie McGrady did not stand. |
| South East Cambridgeshire | | Conservative | | (C) | |
| South East Cornwall | | Liberal Democrats | | (C) | Gain. Previous incumbent Colin Breed did not stand. |
| South Holland and The Deepings | | Conservative | | (C) | |
| South Leicestershire | | Conservative | | (C) | MP for predecessor seat of Blaby. |
| South Norfolk | | Conservative | | (C) | |
| South Northamptonshire | | Conservative | | (C) | New constituency. |
| South Ribble | | Labour | | (C) | Gain. Defeated incumbent David Borrow. |
| South Shields | | Labour | | (L) | |
| South Staffordshire | | Conservative | | (C) | Previous incumbent Sir Patrick Cormack did not stand. |
| South Suffolk | | Conservative | | (C) | |
| South Swindon | | Labour | | (C) | Gain. Defeated incumbent Anne Snelgrove. |
| South Thanet | | Labour | | (C) | Gain. Defeated incumbent Stephen Ladyman. |
| South West Bedfordshire | | Conservative | | (C) | |
| South West Devon | | Conservative | | (C) | |
| South West Hertfordshire | | Conservative | | (C) | |
| South West Norfolk | | Conservative | | (C) | Previous incumbent Christopher Fraser did not stand. |
| South West Surrey | | Conservative | | (C) | |
| South West Wiltshire | | Conservative | | (C) | MP for predecessor seat of Westbury. |
| Southampton, Itchen | | Labour | | (L) | |
| Southampton, Test | | Labour | | (L) | |
| Southend West | | Conservative | | (C) | |
| Southport | | Liberal Democrats | | (LD) | |
| Spelthorne | | Conservative | | (C) | Previous incumbent David Wilshire did not stand. |
| St Albans | | Conservative | | (C) | |
| St Austell and Newquay | | Liberal Democrats | | (LD) | New constituency. |
| St Helens North | | Labour | | (L) | |
| St Helens South and Whiston | | Labour | | (L) | MP for predecessor seat of St Helens South. |
| St Ives | | Liberal Democrats | | (LD) | |
| Stafford | | Labour | | (C) | Gain. Defeated incumbent David Kidney. |
| Staffordshire Moorlands | | Conservative | | (C) | Gain. Notional hold following boundary changes. Defeated incumbent Charlotte Atkins. |
| Stalybridge and Hyde | | Labour | | (L Co-op) | Previous incumbent James Purnell did not stand. |
| Stevenage | | Labour | | (C) | Gain. Previous incumbent Barbara Follett did not stand. |
| Stirling | | Labour | | (L) | |
| Stockport | | Labour | | (L) | |
| Stockton North | | Labour | | (L) | Previous incumbent Frank Cook did not stand. |
| Stockton South | | Labour | | (C) | Gain. Defeated incumbent Dari Taylor. |
| Stoke-on-Trent Central | | Labour | | (L) | Previous incumbent Mark Fisher did not stand. |
| Stoke-on-Trent North | | Labour | | (L) | |
| Stoke-on-Trent South | | Labour | | (L) | |
| Stone | | Conservative | | (C) | |
| Stourbridge | | Labour | | (C) | Gain. Defeated incumbent Lynda Waltho. |
| Strangford | | DUP | | (DUP) | Seat vacant due to resignation of previous incumbent Iris Robinson. |
| Stratford-on-Avon | | Conservative | | (C) | Previous incumbent John Maples did not stand. |
| Streatham | | Labour | | (L) | Previous incumbent Keith Hill did not stand. |
| Stretford and Urmston | | Labour | | (L) | Previous incumbent Beverley Hughes did not stand. |
| Stroud | | Labour | | (C) | Gain. Defeated incumbent David Drew. |
| Suffolk Coastal | | Conservative | | (C) | Previous incumbent John Gummer did not stand. |
| Sunderland Central | | Labour | | (L) | MP for predecessor seat of Sunderland North, Bill Etherington, did not stand. |
| Surrey Heath | | Conservative | | (C) | |
| Sutton and Cheam | | Liberal Democrats | | (LD) | |
| Sutton Coldfield | | Conservative | | (C) | |
| Swansea East | | Labour | | (L) | |
| Swansea West | | Labour | | (L Co-op) | Previous incumbent Alan Williams did not stand. |
| Tamworth | | Labour | | (C) | Gain. Defeated incumbent Brian Jenkins. |
| Tatton | | Conservative | | (C) | |
| Taunton Deane | | Liberal Democrats | | (LD) | MP for predecessor seat of Taunton. |
| Telford | | Labour | | (L) | |
| Tewkesbury | | Conservative | | (C) | |
| Thirsk and Malton | | Conservative | | (C) | Formerly MP for Vale of York. MP for predecessor seat of Ryedale, John Greenway, did not stand. The poll was the only one postponed.
Not a by-election as without a new campaign round. This was due to the death of the UKIP candidate. |
| Thornbury and Yate | | Liberal Democrats | | (LD) | MP for predecessor seat of Northavon. |
| Thurrock | | Labour | | (C) | Gain. Previous incumbent Andrew MacKinlay did not stand. |
| Tiverton and Honiton | | Conservative | | (C) | Previous incumbent Angela Browning did not stand. |
| Tonbridge and Malling | | Conservative | | data-sort-value="Stanley, John" | Sir John Stanley (C) | |
| Tooting | | Labour | | (L) | |
| Torbay | | Liberal Democrats | | (LD) | |
| Torfaen | | Labour | | (L) | |
| Torridge and West Devon | | Conservative Party | | (C) | |
| Totnes | | Conservative | | (C) | Previous incumbent Anthony Steen did not stand. |
| Tottenham | | Labour | | (L) | |
| Truro and Falmouth | | Liberal Democrats | | (C) | MP for predecessor seat of Truro and St Austell, Matthew Taylor, did not stand. |
| Tunbridge Wells | | Conservative | | (C) | |
| Twickenham | | Liberal Democrats | | (LD) | |
| Tynemouth | | Labour | | (L) | |
| Upper Bann | | DUP | | (DUP) | |
| Uxbridge and South Ruislip | | Conservative | | (C) | MP for predecessor seat of Uxbridge. |
| Vale of Clwyd | | Labour | | (L) | |
| Vale of Glamorgan | | Labour | | (C) | Gain. Previous incumbent John Smith did not stand. |
| Vauxhall | | Labour | | (L) | |
| Wakefield | | Labour | | (L) | |
| Wallasey | | Labour | | (L) | |
| Walsall North | | Labour | | (L) | |
| Walsall South | | Labour | | (L) | Previous incumbent Bruce George did not stand. |
| Walthamstow | | Labour | | (L Co-op) | Previous incumbent Neil Gerrard did not stand. |
| Wansbeck | | Labour | | (L) | Previous incumbent Denis Murphy did not stand. |
| Wantage | | Conservative | | (C) | |
| Warley | | Labour | | (L) | |
| Warrington North | | Labour | | (L) | |
| Warrington South | | Labour | | (C) | Gain. Previous incumbent Helen Southworth did not stand. |
| Warwick and Leamington | | Labour | | (C) | Gain. Defeated incumbent James Plaskitt. |
| Washington and Sunderland West | | Labour | | (L) | MP for predecessor seat of Gateshead East and Washington West. |
| Watford | | Labour | | (C) | Gain. Defeated incumbent Claire Ward. |
| Waveney | | Labour | | (C) | Gain. Defeated incumbent Bob Blizzard. |
| Wealden | | Conservative | | (C) | |
| Weaver Vale | | Labour | | (C) | Gain. Previous incumbent Mike Hall did not stand. |
| Wellingborough | | Conservative | | (C) | |
| Wells | | Conservative | | (LD) | Gain. Defeated incumbent David Heathcoat-Amory. |
| Welwyn Hatfield | | Conservative | | (C) | |
| Wentworth and Dearne | | Labour | | (L) | MP for predecessor seat of Wentworth. |
| West Aberdeenshire and Kincardine | | Liberal Democrats | | data-sort-value="Smith, Robert" | Sir Robert Smith, Bt (LD) | |
| West Bromwich East | | Labour | | (L) | |
| West Bromwich West | | Labour | | (L Co-op) | |
| West Dorset | | Conservative | | (C) | |
| West Dunbartonshire | | Labour | | (L Co-op) | Previous incumbent John McFall did not stand. |
| West Ham | | Labour | | (L) | |
| West Lancashire | | Labour | | (L) | |
| West Suffolk | | Conservative | | (C) | Previous incumbent Richard Spring did not stand. |
| West Tyrone | | Sinn Féin | | (SF) | |
| West Worcestershire | | Conservative | | (C) | Previous incumbent Sir Michael Spicer did not stand. |
| Westminster North | | Labour | | (L) | MP for predecessor seat of Regent's Park and Kensington North. |
| Westmorland and Lonsdale | | Liberal Democrats | | (LD) | |
| Weston-super-Mare | | Conservative | | (C) | |
| Wigan | | Labour | | (L) | Previous incumbent Neil Turner did not stand. |
| Wimbledon | | Conservative | | (C) | |
| Winchester | | Liberal Democrats | | (C) | Gain. Previous incumbent Mark Oaten did not stand. |
| Windsor | | Conservative | | (C) | |
| Wirral South | | Labour | | (L) | Previous incumbent Ben Chapman did not stand. |
| Wirral West | | Conservative | | (C) | Gain. Notional hold following boundary changes. Previous incumbent Stephen Hesford did not stand. |
| Witham | | Conservative | | (C) | New constituency. |
| Witney | | | | (C) | Appointed Prime Minister on 11 May |
| Woking | | | | (C) | Previous incumbent Humfrey Malins did not stand. |
| Wokingham | | Conservative | | (C) | |
| Wolverhampton North East | | Labour | | (L) | Previous incumbent Ken Purchase did not stand. |
| Wolverhampton South East | | Labour | | (L) | |
| Wolverhampton South West | | Labour | | (C) | Gain. Defeated incumbent Rob Marris. |
| Worcester | | Labour | | (C) | Gain. Defeated incumbent Michael John Foster. |
| Workington | | Labour | | (L) | |
| Worsley and Eccles South | | Labour | | (L) | MP for predecessor seat of Worsley. |
| Worthing West | | Conservative | | data-sort-value="Bottomley, Peter" | Sir Peter Bottomley (C) | |
| The Wrekin | | Conservative | | (C) | |
| Wrexham | | Labour | | (L) | |
| Wycombe | | Conservative | | (C) | Previous incumbent Paul Goodman did not stand. |
| Wyre and Preston North | | Conservative | | (C) | New constituency. Formerly MP for Lancaster and Wyre. |
| Wyre Forest | | Health Concern | | (C) | Gain. Defeated incumbent Richard Taylor. |
| Wythenshawe and Sale East | | Labour | | (L) | |
| Yeovil | | Liberal Democrats | | (LD) | |
| Ynys Môn (Anglesey) | | Labour | | (L) | |
| York Central | | Labour | | (L) | MP for predecessor seat of City of York. |
| York Outer | | Liberal Democrats | | (C) | Notional gain following boundary changes. MP for predecessor seat of Vale of York, Anne McIntosh, won in Thirsk and Malton. | |
After a general election, changes can occur in the composition of the House of Commons. This happens as a result of the election of Deputy Speakers, by-elections, defections, suspensions or removal of whip.
The net outcome of all changes at the dissolution of Parliament resulted in four fewer Conservative MPs, two fewer Labour MPs, one fewer Liberal Democrat MP, four more independent MPs, the addition of one Respect MP and the addition of two UKIP MPs. This resulted in a reduction of the actual government majority from eighty-three to seventy-three. Both Respect and UKIP were previously unrepresented in the fifty-fifth Parliament. This was the first time that candidates standing for UKIP had been elected to the House of Commons.
Although Deputy Speakers do not resign from their parties, they cease to vote (except to break ties) and they do not participate in party-political activity until the next election.
By-elections are held for seats that become vacant, although if a vacancy occurs close to a general election, the seat may remain vacant for the remainder of the Parliament.[8]
In some situations, the label which MPs sit in the House of Commons under can change. When this happens, MPs often become independents.
