An election to the 56th Parliament of the United Kingdom for the constituency area of Cities Of London and Westminster, held as part of the general election on 7 May 2015.
Conservative hold by Mark Field with a majority of 9,671 - 26.7% - on a turnout of 59.3%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| FIELD, Mark | Con | 19,570 | 54.1% | 1.9% |
| SLINGSBY, Nik | Lab | 9,899 | 27.4% | 5.2% |
| BROOKS-GORDON, Belinda | LD | 2,521 | 7.0% | -13.5% |
| SMALL, Hugh | Green | 1,953 | 5.4% | 3.3% |
| STEPHENSON, Robert | UKIP | 1,894 | 5.2% | 3.4% |
| DESFORGES, Edouard-Henri | CSA | 160 | 0.4% | - |
| MCLACHLAN, Jill | CPA | 129 | 0.4% | - |
| CLIFFORD, Adam | CW | 59 | 0.2% | - |
Under section 13(b) of the Representation of the People Act 1985, a candidate gaining 5% or less of the vote share will forfeit their deposit.
An electorate of 60,992, having a valid vote count of 36,185 and an invalid vote count of 167.
Result declared at 02:54 on 8 May 2015.