Leading article: Clegg must hold out for PR

We all, sadly, feared it: that the Liberal Democrat surge in the opinion polls following the first leaders' television debate would dissipate, and, in the end, the slow puncture was more like a catastrophic blow-out.

No one could quite believe the exit poll published the moment voting ended on Thursday, yet, through a morning of peculiar, unpredictable results, it proved bang on the money. Nick Clegg had indeed been squeezed hard, and normal service resumed in an electoral system suited simply to two heavyweights slugging it out.

Except that, this time, the consequences are different. We have voted for a hung parliament. Despite his disappointments, that gives Mr Clegg a position of great significance. So, as he wrestles with the affections of David Cameron and Gordon Brown, and weighs up the national interest, a portentous abstraction repeated by all on Friday, what should he do?

We respect Mr Clegg's position that the Conservative Party leader deserves the first chance to woo him. The Tories polled two million votes more than Labour, and at 306 seats, nearly 50 ahead of Labour, Mr Cameron is pretty close to the 326-seat finishing line.

But is Mr Cameron's "big, open and comprehensive" offer outlined in his impressive manner really what it seems? There will be, he has said, no negotiating on the timing of cuts in public spending. Nor on renewing the Trident programme. Nor on the Tories' lamentable approach to our European partners – where's the national interest in that? Nor on immigration.

True, Mr Clegg might win the odd dog biscuit. More money for schools with disadvantaged pupils; a slightly more progressive approach to income tax; and they don't disagree on identity cards. But, as we argued last week, and as 1,000 demonstrators gathered in London's Smith Square yesterday to remind him, there is one issue above all others on which Mr Clegg needs to focus. That is the reform of an electoral system which required 119,000 votes to elect each Lib Dem MP, while the Tories needed 35,000 and each Labour MP a mere 33,000. It is an overwhelming injustice and an affront to democracy.

Unfortunately, Mr Clegg has sent out conflicting signals: that the lack of an offer of electoral reform was a block to a coalition deal, and then that it was not. Mr Cameron's offer of a talking shop is Roy Jenkins Lite. We've been there, and we know what the outcome will be.

Mr Brown, in his own dogged way, waits ready to pounce. He has already offered a not-necessarily-more-proportional system and on Friday he tried to spoil the two younger men's dalliance, with a hint that a more proportional system might be put to a referendum.

How keenly, then, we feel the loss of Alan Watkins, our veteran political commentator, who died yesterday and who used to write about the prospect of a hung parliament with such amused scepticism.

He would have explained why Mr Clegg might decide that either a formal deal or a "confidence and supply" arrangement with the Tories might be the best approach. And he would have mused lightly on the idea that Mr Clegg might prop up Gordon Brown – in a "coalition of losers" – and how it might come close to fomenting civil disturbance.

Mr Clegg may – and here is the rub – believe that to join with Mr Brown in those circumstances, and then to take his case for electoral reform to the electorate, in the teeth of a hostile press, would end in certain defeat, thereby consigning the cause to the dustbin for another 30 or 50 years. That is indeed a risk.

But remember this? "There is the chance to resettle things in a new way. It is very unusual and I don't want people to be bamboozled or bullied or frightened by the other parties into saying they cannot take a chance on big change this time." That is what Mr Clegg told this paper last week. "Let us not squander this once-in-a-generation chance."

They were stirring words, and apply today to the choice he faces. This may be the greatest gamble Mr Clegg will ever make – but it is a gamble that those on the progressive wing of British politics believe he cannot duck. Put Mr Cameron in No 10, formally or not, and the Lib Dems get a little bit of what they want, and maybe one or two of them will get a warmish glow. Bet the house on red (rather than on Mr Brown, who will surely stand down soon), and the Lib Dems get what they have wanted for generations: a chance to sweep away a corrupt and discredited system, and maybe, just maybe, win the greatest single change to our constitution in 100 years. We suggest the latter.