The General Election could have been so different.

We know the actual result: the first majority Conservative Government for 20 years, the Liberal Democrats reduced to a rump, almost total domination of Scotland by the SNP and Labour making little or no progress. But that was under the traditional first-past-the-post voting system used for general elections. What if proportional representation had been used instead?

The answer, according to the Electoral Reform Society's report on the election, is that the Tories would have come nowhere near outright victory. On the night, under first-past-the-post, they achieved 331 seats, giving them a slim majority, but under the single transferable vote system, that number would have been reduced to 276. Apart from Labour, the other parties would also have had radically different outcomes. The SNP for example would have won 34 seats rather than 56, the Lib Dems would have finished with 26 rather than eight and, in the biggest change of all, UKIP would have 54 seats instead of one.

Such a result could not please everyone and would be particularly troubling for those who worry about the rise of UKIP or are wary of constant coalition seen in other countries such as Israel or Italy. But it has been obvious for many years now that the first-past-the-post system does not properly reflect how people vote and that with three major parties now in England and four in Scotland, the deficiencies of first-past-the-post are deepening. In fact, in its report, the Electoral Reform Society calls this election the most disproportionate in British electoral history.

The danger of ignoring that reality and sticking with first past the post regardless (as the Tories may be tempted to do after winning under it) is that the imbalances in the system will lead to resentment and even more distortions in the future as people vote tactically in an attempt to get round it. The Electorial Reform Society points out that half the votes cast on May 7th went to losing candidates and that 331 MPs were elected on under 50 per cent of the vote, leaving millions of voters with the feeling that their vote did not count. The society also suggests that nearly three million voters are likely to have voted tactically.

The problems are particularly obvious in Scotland, with the SNP taking virtually all the seats on half the vote, meaning that Unionist opinion is unrepresented in all but three of the Scottish constituencies, although all the parties are affected in some way. Both the Labour party and the Conservatives are now chronically under-represented in Scotland, with the Tories having one seat on 15 per cent of the vote and Labour faring even worse with one seat on 24 per cent. There are similar imbalances across the UK, with the Tories under-represented in the north of England and Labour over-represented in Wales.

There are some parties who may think that, despite these imbalances, their interest lies in sticking with first past the post, but the system is no longer fair or sustainable in the face of a number of profound changes in how the UK is shaped and how its citizens vote. Not only are voters supporting a much greater range of parties, we are heading towards a more federal, devolved, multi-parliament structure that will make the old voting system designed for two parties fighting over one parliament even more archaic and irrelevant.

To its credit, the SNP has maintained its support for change, despite just benefiting from first past the post, and it is now for the Tories to overcome their surprise and delight at winning three weeks ago and recognize the new political reality. The Tory argument in favour of retaining first-past-the-post has always been that it produces stable government, while Labour has championed the link between constituents and their MPs, but the democratic deficit produced by a high number of safe seats in which many people feel their votes do not count has become too great. The Electoral Reform Society has called its report A Voting System in Crisis - an urgent cross-party consensus is now needed to change it.