Bruce Anderson: There is every reason why the PM should go for an early election. Except that he won't

He has enjoyed unsettling the Tories with election rumours, so why not continue?

There are three arguments for an early election: the polls, events and the mandate. There are also three reasons for delay: the polls, events and the mandate. If Gordon Brown had enjoyed a steady 10 per cent poll lead for the past few months, he would be foolish to wait. But the polls have been bouncing around. Although the latest one showed a six-point Labour lead, that was two down from the previous month. With polls, the trend can be as important as the figures.

Labour also has worries about the marginals, and Scotland. During the past three elections, Labour's organisation in the marginals was superior to the Tories' one. That is no longer the case. Apropos of Scotland, Gordon Brown is not the only politician who has done well over the past few months. Alex Salmond has been foot-perfect. There are suggestions that the Nats could gain up to a dozen Labour seats. Even if this seems unlikely, Labour is in bad shape north of the border. On the new boundaries, Mr Brown has to lose only about 25 seats to forfeit his overall majority. Though he has good relations with Ming Campbell, he does not want to share a hung parliament with him.

A six-point poll lead is fine if you have to call an election: less so, when there are other options. In periods of political volatility and widespread voter apathy, lowish poll leads could prove as reliable as the witches in Macbeth, or navigational beacons on the Cornish coast during the era of wreckers.

Volatility brings us to events. To everyone's surprise – including Gordon Brown's – the Northern Rock degringolade does not appear to have damaged the Government's standing. That might seem to be an argument for holding the election before something else goes wrong. But what if it does, during the campaign: a renewed outbreak of foot-and-mouth, say, or tragic news from Iraq or Afghanistan?

Finally, what about the event of events: Europe? Although the Tories would be foolish to fight a single-issue campaign on the EU constitution, the referendum question would be bound to register. A continued refusal to grant one would deprive Mr Brown of any hope of The Sun's support. The PM believes that given time, the European issue will go away. In that case, why not provide the time?

Finally, the mandate; who now believes that Gordon Brown needs one? He has planted his feet very firmly under the No 10 desk. It already seems as if he has been PM for a long time. Nor is there any need to hold an election in order to consign his predecessor to history. What's-his-name, whom he replaced, has disappeared from the political agenda more completely than any retiring PM since Anthony Eden. There is no public demand for a renewed mandate, and that could be a problem in an early election.

The political class adores elections. Because it talks mainly to itself, however, it may fail to realise that this bizarre taste is not widely shared. Observing the 2005 election up country, I came to the conclusion that most real people regard general elections as the equivalent of the circus coming to town. There are amusing aspects: running into well-known faces in the high street. There are irritating ones: the constant trudge from the doormat to the dustbin to dump all the unwanted literature. The public knows that these electoral circuses occur from time to time, but has no wish to see more of them. In the pubs and bus queues, the voters are not yet insisting on the need for an early ballot. That might make Mr Brown pause.

So might the irrevocable nature of the decision. In 1983, when the parliament was four years old, it was clear that Margaret Thatcher would win the election. Nothing could go wrong. The only interesting question was whether dear old Michael Foot could keep his percentage ahead of the Liberal/SDP Alliance's. Yet the Iron Lady agonised. She knew that once she fired the starting gun, there was no way of claiming that it had been an accidental discharge – and there was a difference between her then and Gordon Brown now. She was certain to triumph.

It is the loneliest decision. That brings us to the psychology of the individual. Gordon Brown does not confide in me; his big tent only extends so far. But he may be oscillating between two catchphrases. Is this "as good as it gets" for him, which happens to be David Cameron's view? In that case, Mr Brown must go, now. Or is it a matter of "things can only get better", a Labour slogan from 1997? If so, take the long view. Do not try to put the Opposition out of its misery. Prolong the misery.

That may be in line with Gordon Brown's instincts. He has enjoyed the past few months. Many people, including many Labour MPs, wondered whether he could do politics. He has shown them. There were fears that Tony Blair's supporters would start a guerrilla war. Tony who? Gordon Brown spent 10 years gnawing his flesh with frustration. Those days are over. He is in command of the Government machine and, apparently, the political narrative. He does not see anything on the horizon to threaten that mastery. So why not let it relentlessly unfold, until he does have the secure 10-point lead and the prospect of an increased majority.

He has enjoyed unsettling the Tories with election rumours. He thinks that he can continue to play similar games almost indefinitely. So why not use political tactics to keep the Tories on the wrong foot, while implementing his strategy for government? That, I suspect, is his intention.

There is a further factor. Although it is now impossible to classify Mr Brown in terms of the political categories of the 1970s and 1980s, he used to be a socialist. He read all the texts. These days, little of that is left except for two convictions, both of them central to his political momentum. First, that the state is always right; second, that the Left is always right. Like many people on the political left, he believes that left-wing governments enjoy a moral monopoly. The Right is always wrong.

In the current context, this is reinforced by class. Gordon Brown cannot abide Eton and Oxford. So he cannot accept that anyone who was educated at those institutions could possibly be an intellectual rival. Any distinctions which David Cameron may have obtained must be some upper-class plot to gild phoneyism.

Gordon Brown is a son of the manse. David Cameron's parents lived in an old rectory. It is inconceivable to Mr Brown that a son of the old rectory could ever defeat a son of the manse.

For that reason, I believe that he will not hold an early election. I also think that he is unwise to delay, and to underrate David Cameron. Gordon Brown was never prone to believe in his own capacity for error, and the events of the past few weeks have hardly taught him humility. Yet the words on his political memorial may still read: "Here lies the man who underestimated David Cameron."