The final campaign opinion polls from May 2015 are listed here
| Pollster | Sample dates | Sample size | CON% | LAB% | LIB% | UKIP% | Green% |
|---|---|---|---|---|---|---|---|
| ELECTION 2010 | 6 May 2010 | 37.0 | 29.7 | 23.6 | 3.2 | 1.0 | |
| TNS BMRB | 30 Apr 2015 - 04 May 2015 | 1,185 | 33 | 32 | 8 | 14 | 6 |
| The Sun/YouGov | 04 May 2015 - 05 May 2015 | 2,148 | 34 | 34 | 9 | 12 | 5 |
| Opinium | 04 May 2015 - 05 May 2015 | 2,960 | 35 | 34 | 8 | 12 | 6 |
| The Guardian/ICM | 03 May 2015 - 06 May 2015 | 2,023 | 35 | 35 | 9 | 11 | 4 |
| Daily Mirror/Survation | 04 May 2015 - 06 May 2015 | 4,088 | 31 | 31 | 10 | 16 | 5 |
| Daily Mail; ITV News/ComRes | 05 May 2015 - 06 May 2015 | 1,007 | 35 | 34 | 9 | 12 | 4 |
| Evening Standard/Ipsos-MORI | 05 May 2015 - 06 May 2015 | 1,186 | 36 | 35 | 8 | 11 | 5 |
| Populus | 05 May 2015 - 07 May 2015 | 3,917 | 34 | 34 | 9 | 13 | 5 |
| Poll Average | 30 Apr 2015 - 07 May 2015 | 18,514 | 33.7 | 33.4 | 8.9 | 13.0 | 5.1 |
| SportingIndex | 06 May 2015 - 06 May 2015 | 18,500 | 33.3 | 29.0 | 13.0 | 12.9 | 5.2 |
| AVERAGE | 30 Apr 2015 - 07 May 2015 | 37,014 | 33.5 | 31.2 | 11.0 | 13.0 | 5.1 |
| Actual Result | 07 May 2015 | 37.8 | 31.2 | 8.1 | 12.9 | 3.8 |
The pollsters had the gap between the Conservatives and Labour quite wrong. They saw a gap of just 0.3%, but the actual gap was 6.6%. They had the smaller parties more correct, though slightly overstated the Green party. The betting markets were a bit closer, but significantly overestimated the Liberal Democrats.
| Pollster | Sample dates | Sample size | CON% | LAB% | LIB% | UKIP% | Green% | SNP% |
|---|---|---|---|---|---|---|---|---|
| ELECTION 2010 | 6 May 2010 | 16.7 | 42.0 | 18.9 | 0.7 | 0.7 | 19.9 | |
| Sunday Times/Panelbase | 20 Apr 2015 - 23 Apr 2015 | 1,044 | 16 | 27 | 4 | 3 | 2 | 48 |
| Daily Record/Survation | 22 Apr 2015 - 27 Apr 2015 | 1,015 | 14 | 26 | 5 | 2 | 1 | 51 |
| STV News/Ipsos-MORI | 22 Apr 2015 - 27 Apr 2015 | 1,071 | 17 | 20 | 5 | 1 | 2 | 54 |
| YouGov aggregation | 31 Mar 2015 - 29 Apr 2015 | 2,225 | 16 | 28 | 6 | 4 | 3 | 43 |
| Sunday Times/YouGov | 29 Apr 2015 - 01 May 2015 | 1,162 | 15 | 26 | 7 | 2 | 1 | 49 |
| Poll Average | 20 Apr 2015 - 01 May 2015 | 6,517 | 15.7 | 25.9 | 5.5 | 2.7 | 2.0 | 47.9 |
| Actual Result | 07 May 2015 | 14.9 | 24.3 | 7.5 | 1.6 | 1.3 | 50.0 |
The pollsters were more accurate for the Scottish voting intention. Although UKIP and the Greens were estimated a little high, and the SNP and the Lib Dems were a little low, the result was broadly in line with the predicted vote shares.