These are the seats where the winning party had the narrowest lead over the third-place party in December 2019.
Which seats will have the narrowest majorities at the next election? see Predicted Closest Three-Way Marginal Seats.
| Constituency | Winner | Second | Third | Votes Required | ||||
|---|---|---|---|---|---|---|---|---|
| Ynys Mon | Conservative | 12,959 | Labour | 10,991 | Plaid Cymru | 10,418 | 2,541 | 4.89% |
| Barnsley East | Labour | 14,329 | Reform/Brexit | 11,112 | Conservative | 10,377 | 3,952 | 5.69% |
| Hartlepool | Labour | 15,464 | Conservative | 11,869 | Reform/Brexit | 10,603 | 4,861 | 6.86% |
| Sheffield, Hallam | Labour | 19,709 | Liberal Democrat | 18,997 | Conservative | 14,696 | 5,013 | 6.89% |
| East Lothian | SNP | 21,156 | Labour | 17,270 | Conservative | 15,523 | 5,633 | 6.90% |
| Cities Of London and Westminster | Conservative | 17,049 | Liberal Democrat | 13,096 | Labour | 11,624 | 5,425 | 8.52% |
| Ashfield | Conservative | 19,231 | Other | 13,498 | Labour | 11,971 | 7,260 | 9.28% |
| South Antrim | DUP | 15,149 | UUP | 12,460 | Alliance | 8,190 | 6,959 | 9.70% |
| Kirkcaldy and Cowdenbeath | SNP | 16,568 | Labour | 15,325 | Conservative | 9,449 | 7,119 | 9.77% |
| Doncaster North | Labour | 15,740 | Conservative | 13,370 | Reform/Brexit | 8,294 | 7,446 | 10.29% |
See also: Electoral Analysis