AV would have given South-East 10 different MPs, says new study

Ten seats in London and the South-East would now be in different hands if the alternative voting system had been used at last year's general election, research reveals today.

The Liberal Democrats would have been the big winners, taking four seats each from Labour and the Tories.

Labour would have gained two seats from the Conservatives - leaving David Cameron's party with six fewer MPs in the region.

The altered political map is revealed in an academic analysis of British Election Study data collected immediately after last May's poll, which delivered a hung parliament. It comes just a month before May 5's referendum on changing the electoral system.

Voters will be asked whether to stick with the first-past-the-post system, where one candidate is chosen, or switch to AV, where candidates are ranked in order of preference and second preferences taken into account if necessary until someone secures 50 per cent backing.

The last election's highest-profile casualty would have been Chuka Umunna in Streatham, now a close aide to Ed Miliband and tipped as a future Labour leader. His seat would have gone to the Lib-Dems under AV, the study for the journal Parliamentary Affairs concluded.

Labour's other losses to the Lib-Dems would have been shadow health minister Emily Thornberry in Islington South and Finsbury, Jim Dowd in Lewisham West and Penge, and Andrew Smith in Oxford East. But they would have claimed two Tory seats - Mary MacLeod's Brentford and Isleworth and Matthew Offord's Hendon.

Tory losses to the Lib-Dems would have come in Nicola Blackwood's Oxford West and Abingdon, Rob Wilson's Reading East, Anne Main's St Albans and Richard Harrington's Watford.

Academics from the University of Essex and the University of Texas at Dallas carried out the study.

It found that Conservative voters in London were likely to give six per cent of their second preferences to Labour, 50 per cent to the Lib-Dems and the rest to other parties.

Labour voters were likely to give seven per cent of second preferences to the Tories but 59 per cent to the Lib- Dems and the rest to others.

Lib-Dem voters were likely to give 44 per cent of second preferences to Labour, 24 per cent to the Tories and the rest to other parties. Nationwide, the Conservatives would have won 22 fewer seats than they actually did, Labour would have been nine seats down, while the Liberal Democrats would have been 32 seats better off.

The academics said this would have "radically changed" the arithmetic of post-election coalition building because Nick Clegg's party would as a result have been able to form a majority coalition with either the Conservatives or Labour.

The study was highlighted by Helena Djurkovic, chief executive of the Political Studies Association, who said it was evidence that a switch to AV would not have the dramatic effects claimed by voting reform campaigners on both sides of the debate.

"A move to AV would not be a radical change from the current system of First Past the Post," she said.

"Voters should not be scared of AV but neither should they see it as a panacea for all the problems in our political system."