OXFORDSHIRE would have two Liberal Democrat MPs if one type of proportional representation had been used in last week’s General Election, a political expert says.

Oxford University’s Professor of Politics Iain McLean, who specialises in electoral systems and constitutional reform, said the county’s political map would look very different if a single transferable vote (STV) system had been used instead of the current first past the post scheme.

As it stands Oxfordshire has five Conservative MPs; Nicola Blackwood (Oxford West and Abingdon), Ed Vaizey (Wantage), Tony Baldry (Banbury), David Cameron (Witney) and John Howell (Henley), with one Labour MP, Andrew Smith (Oxford East).

Proportional representation (PR) aims to ensure the number of MPs each party wins is proportional to the number of votes cast for that party.

STV works by having electors vote on several candidates in order of preference, as opposed to just picking out their favourite candidate on their own.

MPs are elected for larger constituencies than the current ones based on the proportion of votes they receive.

Prof McClean spoke as the Lib Dems, who want to introduce proportional representation, were talking to both the Conservatives and Labour about how the party could work in a Government led by either main party.

Prof McLean said: “Say Oxfordshire was a six-member constituency elected by STV.

“Each party would put up three candidates and based on current voting numbers it would go three Conservatives, two Liberal Democrats and one Labour.”

The Conservatives gained 47 per cent share of the vote in Oxfordshire, with the Liberal Democrats taking a 27 per cent share and Labour in third with 17 per cent.

Among key Lib Dem issues in entering any coalition is progress on introducing proportional representation for future elections.

The Lib Dems are the biggest losers under the present first-past- the-post system.

Prof McClean said: “This issue is huge and the stakes are very high. If the talks fail, this will be the point they fail on.

“Either the Tories will have to accept some commitment to PR or the Lib Dems will have to drop it.

“Either would be extremely painful for their supporters.”