Notional results for a UK general election on 5 May 2005 Wales - by party
| Party | Constituencies contested | Votes | Vote share | Constituencies won |
| Labour | 40 | 594,821 | 42.7% | 30 |
| Liberal Democrat | 40 | 256,249 | 18.4% | 4 |
| Conservative | 40 | 297,830 | 21.4% | 3 |
| Plaid Cymru | 40 | 174,838 | 12.6% | 2 |
| UK Independence Party | 31 | 20,297 | 1.5% | 0 |
| Green Party | 11 | 7,144 | 0.5% | 0 |
| British National Party | 2 | 1,689 | 0.1% | 0 |
Estimates of the 2005 general election result in new constituencies
Colin Rallings and Michael Thrasher, then at the University of Plymouth, produced estimates of the 2005 general election result as if the new constituencies recommended by the separate Parliamentary Boundary Commissions for England, Wales and Northern Ireland had then been in existence.
The Elections Centre, established by Professors Colin Rallings and Michael Thrasher, moved to the University of Exeter in 2003.