To seize this historic moment, the Lib Dems must turn to Labour.

The Observer newspaper is this morning openly calling for Nick Clegg to do a deal with the Labour party.

Nobody won. That is the basic definition of a hung parliament. The newly elected members might not see it that way. The leaders of the three main parties might couch the results of last week's election in historical and statistical terms that make them feel better. But the fact remains: nobody won.

The Conservatives have the most plausible claim to some kind of victory. They took the highest national share of the vote and gained 97 seats. But Mr Cameron was battling to restore majority Conservative rule. He campaigned vigorously against a hung parliament, all but demanding unchecked power. He was rebuffed: 10.7 million people voted for Tory government; more than 15 million people did not.

But the non-Tory vote was divided, largely between Labour and Liberal Democrats. Despite many local skirmishes, there is a strain of cousinly feeling in both parties that sees the Tories as a common enemy. From that impulse now springs the idea that Labour and the Lib Dems could join forces to prevent Mr Cameron from taking power.

I agree with that logic. Both Labour and the Liberal Democrats represent different sides of the progressive fence. Labour and the Lib Dems agree on far more things than the Liberals and the Tories will ever have in common.

Indeed, as I have said before, many of my friends voted Liberal specifically because they lived in seats where the Liberals were the only serious challengers to the Tory party. They certainly didn't vote Liberal to see Clegg enable the Tory party to take power.

The Observer notes that, under the presidential system epitomised by the recent TV debates, Cameron won. But they remind us that that is not the way our system works.

But the fact remains that victory, under the electoral system we have, means securing a Commons majority. Constitutionally, no other metric matters. If the Conservatives believe that share of vote and lead over the nearest rival should have some moral weight in deciding a winner, they have already conceded a vital point about the need for electoral reform: the proportion of overall support in the country as a whole matters.

Many more people voted against Cameron than voted for him. That is simply a fact.

And Clegg should realise that even although Brown did not win, neither under our constitutional system did Cameron.

Cameron failed to convince the electorate that the Tory party represent the way forward. Indeed, in the whole of Scotland - which voted 40% in favour of Labour - the Tories were elected in one measly seat.

So the Observer are suggesting that Brown should continue in a caretaker capacity only, for no more than two years, to see through electoral reform, the election of a new Labour leader and that a promise be given to go to back to the polls once that has been achieved.

Combined, the Liberal Democrats and Labour have the affinity on policy, the electoral mandate and the unique historic opportunity to usher in a new era of fairer, better governance for Britain. Mr Brown must offer Mr Clegg partnership in an administration of real national renewal and make the vital concession needed to secure it – a guarantee of his own departure.

Mr Clegg should accept those terms. That is how the national interest is best served after the election that nobody won.

The right wing press would go bonkers were this to take place, but the fact of the matter is that, much as Cameron feels he has a sense of entitlement to the keys of Number Ten, his own inability to clearly set out the Conservative stall is the reason he finds himself in his current predicament.

And, if Hague's radical letter concerning Conservative plans for Europe are anything to go by, he didn't campaign on it because he suspected that we might reject it.

Cameron has no-one to blame other than himself.

Click here for Observer leader.

Tags: Clegg, Cameron, Brown, UK election 2010