A February election isn't likely, but you can never be certain with this Prime Minister

If Blair decides to go, it won't be because of Iraq but because he's certain to win and wants to get it over quickly

It would be foolish to give automatic credence to rumours emanating from Tony Blair's Downing Street. The Blair regime does not believe in talking in order to tell the truth. They say whatever is necessary to have the desired effect.

Were Alastair Campbell still in charge, we would know what to make of these reports that the election might be held in February. Alastair would be irritated by the way in which ministers - and Cherie Blair - have virtually announced that the election will be in May. This enables the Government's opponents to start planning on the basis of certainty: a luxury which opponents should never be allowed. So Alastair would have talked up February in order to play on the enemies' nerves and disrupt their preparations.

In his absence, matters might be different. The February scuttlebutt may be more than a cynical ploy. For there is one factor which we should never forget. Elections are stressful. During the First World War. Lord Jellicoe said that he was the only man who could lose the war in an afternoon. Contemplating the hazards of choosing an election date, many prime ministers have felt the same thing. Once that starting gun has been fired, it can never be recalled. Even prime ministers who seem certain to win an election can waver over the timing.

At the beginning of 1983, the result of the imminent election seemed absolutely certain. The Falklands War had been won, the economy was beginning to recover, and Margaret Thatcher was facing Michael Foot. A Tory victory appeared as inevitable as it actually proved to be. However, this did not prevent Mrs Thatcher from agonising.

In that January, I had a conversation with Cecil Parkinson, in which I expressed a view that there was no need to wait; we should call the election at the four-year point. "Do not worry, dear boy," Cecil replied: "The prime ministerial ear is being bent." Over the next few weeks, however, it did not appear to stay bent. In April, I ran into Cecil. "Why is everyone saying that I'm in favour of an early election?" he complained: "I've never been in favour of an early election."

Well, the election was held early and it was a walkover. But if even the Iron Lady dithered on the edge of the swimming pool, when she only had to go through the formality of completing a length in order to secure a triumph, we can tell just how much self-torture that decision involves, especially as all the responsibility falls on the PM's shoulders.

Over the past year, there have been many other signs that Tony Blair is under strain. Serious commentators predicted that he would resign before the summer, or that he would hold an election this November. They did so on the basis of apparently well sourced information from well within Number 10. They did so, indeed, because at various moments Mr Blair was minded to do exactly that.

This was partly due to the domestic problems so lovingly described a few weeks ago by Melvyn Bragg, and which also involved the disruption of a Cabinet session and the interruption of a bilateral meeting in the PM's study between Tony Blair and King Abdullah of Jordan. Until the summer, Mr Blair's fate was an open question. We may have to wait for the memoirs, or at least for further indiscretions from highly placed persons, to find out what made him change his mind.

Was it Cherie, insisting that he did not have to worry about the family? Was it a new access of inner strength on Mr Blair's own part, leading him to decide that he could still do more to ensure his place in history? Was it the conclusion, which he had been gradually moving towards but which finally hit him like a revelation, that Gordon Brown was simply not suited to being Prime Minister - or was it some combination of all three? Given the record of insecurity and uncertainty, it is not inconceivable that Mr Blair himself would like to get the next election out of the way as soon as possible.

If so, that is unlikely to have much to do with the Iraqi election. It has been suggested that Mr Blair would hope to benefit from an Iraqi bounce. He is much more likely to experience the dis-benefits of an Iraqi bomb. The best that can be hoped for from an election in Iraq is that it takes place at all, it passes off with only a few hundred deaths, and that Mr Allawi survives and is able to form a government.

None of this is likely to excite British voters. People who are inclined to be angry with a government that has doubled their council tax while trashing their pension will not be comforted by the thought that there is a democratic parliament in Baghdad. No: if Tony Blair should hold an election in February, it will because he has decided that as he is certain to win, he may as well get it out of the way as quickly as possible.

If so, that could be a foolish calculation. The British voters do not like being taken for granted. They expect parliaments to last for around four years, especially when the Government has an impregnable majority. February, a month of dark evenings frequently accompanied by filthy weather, is also an unsatisfactory season for general elections.

Tony Blair would have to give a reason why he had interrupted a parliamentary session, thus writing off the legislative efforts of the previous couple of months, in order to hold an election earlier than expected. The Tories and Liberals would insist that he was compelled to cut and run because of the fear of bad news ahead. It is not certain that all voters would disbelieve them. Tony Blair already has a problem with trust; would a premature election not be seen as a further breach of trust?

But there is one reason why Mr Blair might take the risk. His advisers are planning a negative campaign: possibly the most negative in British electoral history. They want to refight the 1997 election, using Michael Howard to reinforce the unhappy memories which they hope that the voters still have about the John Major government. There will be little attempt to stress positive features of the Blair government. It will be more a matter of "better the devil you have come to know over the past eight years than the one which you came to loathe in the mid 1990s".

On present polling trends, this might work. There is little evidence that Michael Howard has succeeded in making a positive impression on the voters whom he needs to win over, and a four-week battering from Labour propaganda will hardly help him to do so. Yet Tony Blair is dissatisfied by all this negativity. He has not given up hope of making a positive impression on the voters, of finding some means to highlight his successes - as he sees them - and of reanimating the idealism which he inspired in 1997 and which is so vital to his own self esteem.

It is still unlikely that the election will be held earlier than May. Yet the predictions have to take account of the volatile and self-dramatising aspect of the Prime Minister's personality. This is a man who could upset any calculations.