Andrew Grice: The 1983 election shows peril of splitting the anti-Tory vote

Inside the election

(REX FEATURES)

Will we make it?" the Tory frontbencher asked nervously when he rang yesterday. "Do you think we will come fourth?" the Labour official asked later. I thought they were both talking about the election. In fact, they seemed more concerned about whether the team we all support – Spurs – will finish fourth in the Premier League.

I replied "maybe, but it might be a hung parliament" to my Tory friend and "no way!" to the Labour guy. But the fact that, for a fleeting moment, I believed he could contemplate such a Labour meltdown tells us something about the state of play in this remarkable election.

In a week's time, Labour might have fallen off a cliff and come third, and be facing the grim prospect of being supplanted by the Liberal Democrats in a reversal of what happened in the 1920s. Equally, Labour could be in the driving seat of a Lib-Lab progressive alliance, ready to change the voting system – a move which could keep the Tories out of power for a very long time.

Alternatively, David Cameron could be on the steps of Downing Street after winning a comfortable overall majority of about 30 seats. Although Mr Cameron cannot afford any sign of complacency, I sense growing optimism in the Tory camp, after Gordon Brown's disaster in Rochdale and the leaders' final TV debate, that the party will do better in the marginals than the headline polls suggest. "The word is that we will get a majority," whispered a Tory mole. So it might be Lord Ashcroft who won it, despite the wobble caused by Nick Clegg, who has spooked the Tories and Labour alike.

All the same, we shouldn't assume the Tory leader is home and dry because he came top in four of the five polls taken after Thursday's debate. In a way, the instant polls asked the wrong question – "who won?" Surely, the answers tell us more about the respondents' leanings than the performance of the three leaders? These polls have influenced the media coverage of the election race far more than they should have done.

The TV debates are a good thing: they have energised the campaign and are here to stay. But the pre-match build-up and post-match analysis have squeezed out serious discussion of the issues, notably the public services, which have loomed much larger at previous elections. I suspect that has hurt Labour most. Now the TV debates are over, Labour will argue that Mr Cameron's party is largely the "same old Tories" underneath its shiny new surface and that, while the Liberal Democrats have some good values, they do not have the coherent and costed policies to match. Mr Brown will tell voters that a Con-Lib arrangement in a hung parliament would therefore be disastrous for them personally and that only Labour, for all its faults, has the values and policies to deliver the toughness and fairness needed in such serious times.

A hung parliament is still possible. The prospect is certainly being taken very seriously by senior civil servants. "There is a panic going on," one Whitehall insider told me. A lot of officials are frantically brushing up on previously ignored Liberal Democrat policies, so they can flag up common areas of agreement during any horse-trading between the parties. But on the last occasion there was such a last-minute scramble, in 1992, the Tories won outright – and history could repeat itself.

There is no guarantee that Nick Clegg's undoubted success in this campaign will break the mould of British politics. He deserves to, but it is easy to forget amid the excitement that the election is being fought under the old rules and a crazy voting system. Crucially, if the Liberal Democrats hoover up Labour supporters in the 100 key Conservative-Labour marginals, mainly in the North and Midlands, the Tories will be the main beneficiary as they could come through the middle to win many of them.

That is Labour's greatest fear and why its energies will now be channelled into these seats, which will decide the election – albeit in rather different circumstances after the Liberal Democrats' advance than we imagined at the start of the campaign. Expect lots of appeals by Labour to non-Tories to vote tactically (ie for Labour) in these constituencies.

It may look a bit desperate but the history books suggest Labour is right. In 1983, when the SDP-Liberal Alliance was fighting Labour for second place and splitting the anti-Tory vote, Margaret Thatcher won a majority of 144. The mould was not for breaking.

Labour's carefully planned preparations for Thursday's TV debate on the economy, Mr Brown's strongest suit, were nuked by his own actions in Rochdale. As it happens, his so-called "meet the people" strategy was exaggerated, a by-product of internal sniping at Lord Mandelson by the Brown old guard, who alleged that the Prime Minister was being hidden from real people and that all would be well if he could only meet more of them. Enough said.

Labour strategists insist there is still time in this extraordinary campaign for one final twist. Indeed, according to ComRes, 3.7 million people who say they are "absolutely certain to vote" are still making their minds up. Which leader will have the biggest smile on Friday morning? None of them knows what the people will decide.