| Southwark North (1918 - 1950) |
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| Southwark South East (1918 - 1950) |
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| Spelthorne (1918) |
Full name (in Craig 3,4) Middlesex, Spelthorne |
| Spennymoor (1918 - 1950) |
Full name (in Craig 3) Durham, Spennymoor |
| Stalybridge and Hyde (1918) |
Full name (in Craig 3,4) Cheshire, Stalybridge and Hyde |
| Stepney Limehouse (1918 - 1950) |
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| Stepney Mile End (1918 - 1950) |
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| Stepney Whitechapel and St George's (1918 - 1950) |
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| Stirling and Falkirk District of Burghs (1918 - 1950) |
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| Stirlingshire and Clackmannanshire Western (1918 - 1950) |
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| St Marylebone (1918 - 1983) |
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| Stoke Newington (1918 - 1950) |
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| Stoke-on-Trent Burslem (1918 - 1950) |
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| Stoke-on-Trent Hanley (1918 - 1950) |
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| Stoke-on-Trent Stoke (1918 - 1950) |
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| Stone (1918 - 1950) |
Full name (in Craig 3) Staffordshire, Stone. Constituency of same name reformed 1997. |
| Stourbridge (1918 - 1950) |
Full name (in Craig 3) Worcestershire, Stourbridge. Constituency of same name reformed 1997. |
| St Pancras South East (1918 - 1950) |
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| St Pancras South West (1918 - 1950) |
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| Sutton and Cheam (1918) |
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| Swansea East (1918 - 2024) |
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| Swansea West (1918) |
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| Swindon (1918 - 1997) |
Full name (in Craig 3) Wiltshire, Swindon |
| Thurrock (1918) |
Full name (in Craig 3,4) Essex, Thurrock |
| Tonbridge (1918 - 1974) |
Constituency first used at the February General election of 1974 (28/02/1974). Full name (in Craig 3,4) Kent, Tonbridge |