The Hayes and Harlington by-election of 17 June 1971 was held after the death of Labour Member of Parliament (MP) Arthur Skeffington. The seat was retained by Labour.
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Labour | Neville Sandelson | 15,827 | 74.7 | +17.1 | |
| Conservative | Andre William Potier | 5,348 | 25.3 | -15.98 | |
| Majority | 10,479 | 49.4 | +32.99 | ||
| Turnout | 21,175 | 42.3 | -24.9 | ||
| Registered electors | 50,766 | ||||
| Labour hold | Swing | ||||
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Labour | Arthur Skeffington | 19,192 | 57.65 | -4.56 | |
| Conservative | Andre William Potier | 13,728 | 41.24 | +5.54 | |
| Communist | Peter Pink | 372 | 1.12 | -0.98 | |
| Majority | 5,464 | 16.41 | -10.10 | ||
| Turnout | 33,292 | 67.11 | -5.58 | ||
| Registered electors | 49,609 | ||||
| Labour hold | Swing | ||||