PR voting would have left Blair in coalition

Tony Blair would have failed to win an overall majority had the election been held under a system of proportional representation, according to a new study.

Tony Blair would have failed to win an overall majority had the election been held under a system of proportional representation, according to a new study.

A simulation of the last election found that Labour would have at least 120 fewer MPs if the seats were in proportion to the number of votes cast.

The study by experts at the London School of Economics and Oxford University has concluded that there were "levels of distortion of voters' preferences by the electoral system that are very high by international standards".

They found that PR would "make a huge difference to the patterns of political representation across Great Britain". The Liberal Democrat peer Lord Oakeshott of Seagrove Bay, said the "analysis shows how Britain's discredited voting system let Blair scrape back to power".

"With barely one third of the total votes Tony Blair's authority and legitimacy is ebbing away," he said.

Labour gained only 35 per cent of the vote but got 355 MPs because the election was held under first past the post where the winner takes all in constituencies.

Had the election been held under three different PR systems, Labour's support would have slipped by at least 120 seats. The Liberal Democrats would have had at least 80 more MPs.

The Independent's Campaign for Democracy continues to attract support, with nearly 40,000 readers calling for electoral reform.

Charles Kennedy yesterday challenged the Prime Minister over his refusal to reform the voting system. In Prime Minister's Questions he asked whether the election result "accurately reflects what the British public voted for on 5 May".

Liberal Democratstabled a motion calling for "urgent action ... to restore and maintain public confidence in the electoral system".

The research to be published in the book Britain Votes 2005 showed Labour's number of MPs was disproportionately high given their share of the vote.

Patrick Dunleavy, a professor of politics at the London School of Economics, and Helen Margetts, a professor at Oxford University, questioned the "fairness" of the result. Using the PR system of Germany and New Zealand, Labour would have 234 MPs (down from 355) and the Tories would have 210 MPs (up from 197). The Liberal Democrats, who won 62 seats, would have 145, forcing Labour into a coalition pact.

Under the system recommended by Lord Jenkins of Hillhead, in a report commissioned by Mr Blair, Labour would have had to strike a coalition deal. It would have 299 seats, rather than 355, the Tories would have had the same result of 197, and the Liberal Democrats would have taken 107 seats instead of 62.

All three PR systems simulated would see the Greens, UKIP and the BNP win a handful of seats. Each failed to gain a single seat in the 2005 election.

The study shows overall "the Conservatives would stand to gain relatively little from PR" while Labour would lose and the Liberal Democrats and smaller parties such as the Greens would be big gainers.