- Banbury 1660-
- Bandon 1832-1885
- Banff and Buchan 1983-
- Banffshire 1708-1983
- Barking 1918-
- Barkston Ash 1885-1983
- Barnard Castle 1885-1950
- Barnet 1918-1974
- Barnet Chipping Barnet 1974-1983
- Barnet Hendon North 1974-1983
- Barnet Hendon South 1974-1983
- Barnsley 1885-1983
- Barnsley Central 1983-
- Barnsley East 1983-1997
- Barnsley East and Mexborough 1997-
- Barnsley West and Penistone 1983-
- Barnstaple 1660-1950
- Barons Court 1955-1974
- Barrow and Furness 1983-
- Barrow-in-Furness 1885-1983
- Barry 1950-1983
- Basildon 1974-
- Basingstoke 1885-
- Bassetlaw 1885-
- Bath 1660-
- Batley and Morley 1918-1983
- Batley and Spen 1983-
- Battersea 1983-
- Battersea North 1918-1974
- Battersea South 1918-1974
- Battersea and Clapham, Battersea 1885-1918
- Battersea and Clapham, Clapham 1885-1918
- Beaconsfield 1974-
- Beaumaris District of Boroughs 1659-1885
- Bebington 1950-1974
- Bebington and Ellesmere Port 1974-1983
- Beckenham 1950-
- Bedford 1997-
- Bedford 1660-1983
- Bedfordshire 1660-1885
- Bedfordshire Mid 1918-
- Bedfordshire North 1983-1997
- Bedfordshire North East 1997-
- Bedfordshire South 1950-1983
- Bedfordshire South West 1983-
- Bedwellty 1918-1983
- Beeston 1974-1983
- Belfast 1832-1885
- Belfast Cromac 1918-1922
- Belfast Duncairn 1918-1922
- Belfast East 1922-
- Belfast East 1885-1918
- Belfast Falls 1918-1922
- Belfast North 1885-1918
- Belfast North 1922-
- Belfast Ormeau 1918-1922
- Belfast Pottinger 1918-1922
- Belfast Shankill 1918-1922
- Belfast South 1885-1918
- Belfast South 1922-
- Belfast St Anne's 1918-1922
- Belfast Victoria 1918-1922
- Belfast West 1922-
- Belfast West 1885-1918
- Belfast Woodvale 1918-1922
- Belper 1918-1983
- Bere Alston 1660-1832
- Berkshire 1660-1885
- Berkshire East 1983-1997
- Bermondsey 1950-1974
- Bermondsey Rotherhithe 1918-1950
- Bermondsey West Bermondsey 1918-1950
- Berwick and East Lothian 1974-1983
- Berwick-upon-Tweed 1660-
- Berwickshire 1708-1918
- Berwickshire and East Lothian 1950-1974
- Berwickshire and Haddingtonshire 1918-1950
- Berwickshire, Roxburgh and Selkirk 2005-
- Bethnal Green 1950-1974
- Bethnal Green North East 1885-1950
- Bethnal Green South West 1885-1950
- Bethnal Green and Bow 1997-
- Bethnal Green and Stepney 1983-1997
- Beverley 1983-1997
- Beverley 1660-1870
- Beverley 1950-1955
- Beverley and Holderness 1997-
- Bewdley 1660-1950
- Bexhill and Battle 1983-
- Bexley 1945-1974
- Bexley Bexleyheath 1974-1983
- Bexley Erith and Crayford 1974-1983
- Bexley Sidcup 1974-1997
- Bexleyheath 1983-1997
- Bexleyheath and Crayford 1997-
- Biggleswade 1885-1918
- Billericay 1950-
- Bilston 1950-1974
- Birkenhead 1950-
- Birkenhead 1861-1918
- Birkenhead East 1918-1950
- Birkenhead West 1918-1950
- Birmingham 1832-1885
- Birmingham Acock's Green 1918-1950
- Birmingham All Saints 1950-1974
- Birmingham Aston 1918-1974
- Birmingham Bordesley 1885-1918
- Birmingham Central 1885-1918
- Birmingham Deritend 1918-1950
- Birmingham Duddeston 1918-1950
- Birmingham East 1885-1918
- Birmingham Edgbaston 1885-
- Birmingham Erdington 1918-1955
- Birmingham Erdington 1974-
- Birmingham Hall Green 1950-
- Birmingham Handsworth 1918-1983
- Birmingham Hodge Hill 1983-
- Birmingham King's Norton 1918-1974
- Birmingham Ladywood 1918-
- Birmingham Moseley 1918-1950
- Birmingham North 1885-1918
- Birmingham Northfield 1950-
- Birmingham Perry Barr 1950-
- Birmingham Selly Oak 1950-
- Birmingham Small Heath 1950-1997
- Birmingham South 1885-1918
- Birmingham Sparkbrook 1918-1997
- Birmingham Sparkbrook and Small Heath 1997-
- Birmingham Stechford 1950-1983
- Birmingham West 1885-1950
- Birmingham Yardley 1918-
- Bishop Auckland 1885-
- Bishop's Castle 1660-1832
- Blaby 1974-
- Blackburn 1955-
- Blackburn 1832-1950
- Blackburn East 1950-1955
- Blackburn West 1950-1955
- Blackpool 1885-1945
- Blackpool North 1945-1997
- Blackpool North and Fleetwood 1997-
- Blackpool South 1945-
- Blaenau Gwent 1983-
- Blaydon 1918-
- Bletchingley 1660-1832
- Blyth 1950-1983
- Blyth Valley 1983-
- Bodmin 1660-1983
- Bognor Regis and Littlehampton 1997-
- Bolsover 1950-
- Bolton 1832-1950
- Bolton East 1950-1983
- Bolton North East 1983-
- Bolton South East 1983-
- Bolton West 1950-
- Booth Ferry 1983-1997
- Bootle 1885-
- Boroughbridge 1660-1832
- Bossiney 1660-1832
- Boston 1660-1918
- Boston and Skegness 1997-
- Bosworth 1885-
- Bothwell 1918-1983
- Bournemouth 1918-1950
- Bournemouth East 1974-
- Bournemouth East and Christchurch 1950-1974
- Bournemouth West 1950-
- Bow and Poplar 1983-1997
- Brackley 1661-1832
- Bracknell 1997-
- Bradford 1832-1885
- Bradford Central 1885-1955
- Bradford East 1885-1974
- Bradford North 1918-
- Bradford South 1918-
- Bradford West 1885-1918
- Bradford West 1955-
- Braintree 1974-
- Bramber 1660-1832
- Brecon 1660-1885
- Brecon and Radnor 1974-1997
- Brecon and Radnorshire 1997-
- Breconshire 1660-1918
- Breconshire and Radnorshire 1918-1974
- Brent East 1974-
- Brent North 1974-
- Brent South 1974-
- Brentford 1885-1918
- Brentford and Chiswick 1918-1974
- Brentford and Isleworth 1983-
- Brentwood and Ongar 1974-
- Bridgend 1983-
- Bridgnorth 1660-1885
- Bridgwater 1660-1870
- Bridgwater 1885-
- Bridlington 1950-1997
- Bridport 1660-1885
- Brierley Hill 1950-1974
- Brigg 1885-1974
- Brigg and Cleethorpes 1983-1997
- Brigg and Goole 1997-
- Brigg and Scunthorpe 1974-1983
- Brighouse and Spenborough 1950-1983
- Brighton 1832-1950
- Brighton Kemptown 1950-
- Brighton Pavilion 1950-
- Bristol 1660-1885
- Bristol Central 1918-1974
- Bristol East 1983-
- Bristol East 1885-1950
- Bristol North 1885-1950
- Bristol North East 1950-1983
- Bristol North West 1950-
- Bristol South 1885-
- Bristol South East 1950-1983
- Bristol West 1885-
- Bromley 1918-1974
- Bromley Orpington 1974-1983
- Bromley Ravensbourne 1974-1983
- Bromley and Chislehurst 1997-
- Bromsgrove 1950-
- Bromsgrove and Redditch 1974-1983
- Broxbourne 1983-
- Broxtowe 1918-1955
- Broxtowe 1983-
- Buckingham 1660-
- Buckinghamshire 1660-1885
- Buckinghamshire South 1950-1974
- Bucklow 1945-1950
- Buckrose 1885-1950
- Burnley 1868-
- Burton 1885-
- Bury 1832-1950
- Bury North 1983-
- Bury South 1983-
- Bury St Edmunds 1660-
- Bury and Radcliffe 1950-1983
- Bute 1832-1918
- Bute and North Ayrshire 1950-1974
- Bute and Northern 1918-1950
- Buteshire & Caithness 1708-1832
2,145 constituencies in total