- Saffron Walden 1885-
- Salford 1997-
- Salford 1832-1885
- Salford East 1950-1997
- Salford North 1885-1950
- Salford South 1885-1950
- Salford West 1885-1983
- Salisbury 1660-
- Saltash 1660-1832
- Sandwich 1660-1885
- Scarborough 1660-1918
- Scarborough 1974-1997
- Scarborough and Whitby 1997-
- Scarborough and Whitby 1918-1974
- Scunthorpe 1997-
- Seaford 1660-1832
- Seaham 1918-1950
- Sedgefield 1918-
- Selby 1983-
- Selkirkshire 1708-1868
- Sevenoaks 1885-
- Shaftesbury 1660-1885
- Sheffield 1832-1885
- Sheffield Attercliffe 1885-
- Sheffield Brightside 1885-
- Sheffield Central 1885-
- Sheffield Ecclesall 1885-1950
- Sheffield Hallam 1885-
- Sheffield Heeley 1950-
- Sheffield Hillsborough 1918-
- Sheffield Neepsend 1950-1955
- Sheffield Park 1918-1983
- Sherwood 1983-
- Shipley 1885-
- Shoreditch 1918-1950
- Shoreditch Haggerston 1885-1918
- Shoreditch Hoxton 1885-1918
- Shoreditch and Finsbury 1950-1974
- Shoreham 1974-1997
- Shoreham 1660-1885
- Shrewsbury 1660-1983
- Shrewsbury and Atcham 1983-
- Shropshire 1660-1832
- Shropshire North 1983-
- Shropshire Northern 1832-1885
- Shropshire Southern 1832-1885
- Sittingbourne and Sheppey 1997-
- Skipton 1885-1983
- Skipton and Ripon 1983-
- Sleaford 1885-1918
- Sleaford and North Hykeham 1997-
- Sligo 1832-1870
- Sligo 1832-1885
- Sligo North 1885-1922
- Sligo South 1885-1922
- Slough 1983-
- Smethwick 1918-1974
- Solihull 1918-
- Somerset 1660-1832
- Somerset Eastern 1832-1918
- Somerset Mid 1868-1885
- Somerset North 1950-1983
- Somerset Northern 1885-1918
- Somerset Southern 1885-1918
- Somerset Western 1832-1885
- Somerton and Frome 1983-
- South Angus 1950-1974
- South Ayrshire 1918-1974
- South Fylde 1950-1983
- South Hams 1983-1997
- South Holland and The Deepings 1997-
- South Molton 1885-1950
- South Ribble 1983-1997
- South Shields 1832-
- Southall 1918-1974
- Southampton 1660-1950
- Southampton Itchen 1950-
- Southampton Test 1950-
- Southend East 1950-1997
- Southend West 1950-
- Southend-on-Sea 1918-1950
- Southgate 1950-1983
- Southport 1885-
- Southwark 1950-1974
- Southwark 1660-1885
- Southwark Bermondsey 1974-1983
- Southwark Bermondsey 1885-1918
- Southwark Central 1918-1950
- Southwark Dulwich 1974-1983
- Southwark North 1918-1950
- Southwark North and Bermondsey 1997-
- Southwark Peckham 1974-1983
- Southwark Rotherhithe 1885-1918
- Southwark South East 1918-1950
- Southwark West 1885-1918
- Southwark and Bermondsey 1983-1997
- Sowerby 1885-1983
- Spalding 1885-1918
- Spelthorne 1918-
- Spen Valley 1885-1950
- Spennymoor 1918-1950
- St Albans 1660-1852
- St Albans 1885-
- St Andrews District of Burghs 1832-1918
- St Augustine's 1885-1918
- St Austell 1885-1918
- St George's Hanover Square 1885-1918
- St Helens 1885-1983
- St Helens North 1983-
- St Helens South 1983-
- St Ives 1660-
- St Marylebone 1918-1983
- St Pancras East 1885-1918
- St Pancras North 1885-1974
- St Pancras South 1885-1918
- St Pancras South East 1918-1950
- St Pancras South West 1918-1950
- St Pancras West 1885-1918
- St.Germans 1660-1832
- St.Mawes 1660-1832
- Stafford 1660-1950
- Stafford 1983-
- Stafford and Stone 1950-1983
- Staffordshire 1660-1832
- Staffordshire Eastern 1868-1885
- Staffordshire Mid 1983-1997
- Staffordshire Moorlands 1983-
- Staffordshire North Western 1885-1918
- Staffordshire Northern 1832-1885
- Staffordshire South 1983-
- Staffordshire South East 1983-1997
- Staffordshire South West 1974-1983
- Staffordshire Southern 1832-1868
- Staffordshire Western 1868-1918
- Stalybridge 1868-1918
- Stalybridge and Hyde 1918-
- Stamford 1660-1918
- Stamford and Spalding 1983-1997
- Stepney 1950-1974
- Stepney Limehouse 1918-1950
- Stepney Mile End 1918-1950
- Stepney Whitechapel and St George's 1918-1950
- Stevenage 1983-
- Steyning 1660-1832
- Stirling 1983-
- Stirling District of Burghs 1708-1918
- Stirling Falkirk and Grangemouth 1974-1983
- Stirling and Falkirk Burghs 1950-1974
- Stirling and Falkirk District of Burghs 1918-1950
- Stirlingshire 1708-1918
- Stirlingshire East and Clackmannan 1974-1983
- Stirlingshire West 1974-1983
- Stirlingshire and Clackmannanshire Western 1918-1950
- Stockbridge 1660-1832
- Stockport 1832-1950
- Stockport 1983-
- Stockport North 1950-1983
- Stockport South 1950-1983
- Stockton North 1983-
- Stockton South 1983-
- Stockton-on-Tees 1832-1974
- Stoke Newington 1918-1950
- Stoke Newington and Hackney North 1950-1974
- Stoke-on-Trent 1832-1918
- Stoke-on-Trent Burslem 1918-1950
- Stoke-on-Trent Central 1950-
- Stoke-on-Trent Hanley 1918-1950
- Stoke-on-Trent North 1950-
- Stoke-on-Trent South 1950-
- Stoke-on-Trent Stoke 1918-1950
- Stone 1997-
- Stone 1918-1950
- Stourbridge 1918-1950
- Stourbridge 1997-
- Stowmarket 1885-1918
- Strand 1885-1918
- Strangford 1983-
- Stratford-on-Avon 1885-1918
- Stratford-on-Avon 1950-
- Strathkelvin and Bearsden 1983-2005
- Streatham 1983-
- Stretford 1885-1997
- Stretford and Urmston 1997-
- Stroud 1832-
- Sudbury 1885-1950
- Sudbury 1660-1844
- Sudbury and Woodbridge 1950-1983
- Suffolk 1660-1832
- Suffolk Central 1983-1997
- Suffolk Central and Ipswich North 1997-
- Suffolk Coastal 1983-
- Suffolk Eastern 1832-1885
- Suffolk South 1983-
- Suffolk West 1997-
- Suffolk Western 1832-1885
- Sunderland 1832-1950
- Sunderland North 1950-
- Sunderland South 1950-
- Surbiton 1983-1997
- Surbiton 1950-1974
- Surrey 1660-1832
- Surrey East 1950-
- Surrey Eastern 1832-1950
- Surrey Heath 1997-
- Surrey Mid 1832-1885
- Surrey North West 1974-1997
- Surrey South West 1983-
- Surrey Western 1832-1885
- Sussex 1660-1832
- Sussex Eastern 1832-1885
- Sussex Mid 1974-
- Sussex Western 1832-1885
- Sutherland 1708-1918
- Sutton Carshalton 1974-1983
- Sutton Coldfield 1945-
- Sutton Sutton and Cheam 1974-1983
- Sutton and Cheam 1918-
- Swansea District of Boroughs 1832-1918
- Swansea East 1918-
- Swansea Town 1885-1918
- Swansea West 1918-
- Swindon 1918-1997
- Swindon North 1997-
- Swindon South 1997-
2,145 constituencies in total