| Rothwell (1918 - 1950) |
Full name (in Craig 3) Yorkshire (West Riding), Rothwell |
| Royton (1918 - 1950) |
Full name (in Craig 3) Lancashire, Royton |
| Salford North (1885 - 1950) |
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| Salford South (1885 - 1950) |
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| Seaham (1918 - 1950) |
Full name (in Craig 3) Durham, Seaham |
| Sheffield, Ecclesall (1885 - 1950) |
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| Shoreditch (1918 - 1950) |
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| Southampton (1832 - 1950) |
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| Southend-on-Sea (1918 - 1950) |
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| South Molton (1885 - 1950) |
Full name (in Craig 2,3) Devon, South Molton |
| Southwark Central (1918 - 1950) |
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| Southwark North (1918 - 1950) |
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| Southwark South East (1918 - 1950) |
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| Spennymoor (1918 - 1950) |
Full name (in Craig 3) Durham, Spennymoor |
| Spen Valley (1885 - 1950) |
Full name (in Craig 2,3) Yorkshire (West Riding), Spen Valley |
| Stafford (1832 - 1950) |
Full name (in Craig 3) Staffordshire, Stafford. Constituency of same name reformed 1983. |
| 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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| Stockport (1832 - 1950) |
Constituency of same name reformed 1983. |
| 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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