Gordon Brown, said Peter Riddell in yesterday’s Times, “needs an exit strategy, fast.” Well, the EXIT sign is clear. It points away from an autumn election and straight through a stinking pit of slurry; after which, having run a gauntlet of sneering Tories wielding sharp sticks, Mr Brown will have to let the media throw wet sponges at him for a few weeks.

OK, Gordon, go on: bottle it if you want to. Your advisers – hired and self-appointed, they are many – will be telling you there is no other way out of this mess – and that once the dust has settled you will be seen to have acted shrewdly and in pursuance of a longer-term plan to destroy David Cameron’s Tories.

They’ll remind you that backing down won’t be pleasant and won’t be pretty, but you’ll live to fight another day; that the world will have forgotten by Christmas. How the clichés will flow. A slice of humble pie today – better than the poisoned chalice tomorrow of an election that could doom your premiership. So brace yourself to tell a barefaced lie and claim you never set the hare running in the first place, and we all simply dreamt it. Nobody will believe you but – hey – that’s politics.

Even before this column is printed, this argument may have prevailed. Mr Brown may have reached and signalled the same conclusion. No matter. I’m going join the ranks of Mr Brown’s self-appointed advisers to make the case for carrying on regardless into an election now. I think it would be brave, and be seen as brave. I don’t think the Tories do want a election in November, whatever they say; and I don’t think that if Mr Brown bottles it the world really will have forgotten by Christmas.

The Brown brand has been seriously tarnished in the past two weeks. Doubts have been implanted that will not be forgotten. For our Prime Minister now to choose to call an election that he is not constitutionally bound to call, and that he knows he stands a serious chance of losing, offers him a huge if high-risk chance to wipe away the stain. This dip in the polls gives Mr Brown a tremendous opportunity to show he’s not just a calculating street-fighter, but a man prepared to risk his premiership in order to gain the trust of the nation he wants to lead. Such a chance may not come again.

There are less worthy arguments for an early poll. Even on a shrunk margin he would probably win. Though the poll numbers have fluctuated sickeningly over the past few months they do point to a fairly firm Labour vote, with Opposition support slopping around more capriciously. Some have been arguing that it was the Tory promises on inheritance tax this week that caused the latest upward blip; that throwing out tax-cutting candy wins only temporary support; and that a solid campaign and unrelenting spotlight on the comparison between their man and the Tories’ David Cameron would bring the voters back.

It is true that closer examination of yesterday’s Times-Populus poll (taken both before and after Mr Cameron’s speech) suggests that Conservative support grew after the Cameron speech. Support not gathered by the Tory tax promises was won by Mr Cameron’s own appearance. And of course it would be dangerous to suppose that three weeks’ further spotlight either on Tory tax giveaways, on their leader himself, or on Mr Brown, will necessarily redound to Mr Brown’s advantage.

But over the past 100 days the more the public has seen of Mr Brown, the better they’ve liked him. Why might this not be true of the next four weeks? Nor should the Prime Minister be swept away by the argument that he must do more than win, but win big. I’ve advanced it myself. The Tories all will. It would be embarrassing, to be sure, to go in search of a personal democratic mandate, and come back with a sort of “er . . .” from the voters, in the form of a reduced majority. But if it’s enough to govern with, and if Mr Brown has a programme of big things he wants to do in government, then his programme will soon elbow aside sneers about the size of his majority. How many people know what Labour’s majority is now?

The sneers about his character will be harder to shift, but next week he could shift them. Unless he calls and wins the general election for which he has whetted our appetites, the Prime Minister’s standing will suffer the sort of chronic damage that arises when small doubts are sown in the public imagination and left to germinate as new instances of old vices are noticed: such has been the effect of his behaviour over the past few weeks.

Who advised him to try that cheap trick with Margaret Thatcher? Who wrote that empty Bournemouth speech at the smugfest masquerading as Labour’s conference? Who thought it wise to try to trick Sir Menzies Campbell, or to bring into his tent as an adviser a Tory backbencher sacked by his leader for remarks that had been called racist? How well is Mr Brown being advised? Whatever led him to think it was clever to try to destabilise a Tory conference with an announcement in Iraq on troop withdrawals – and then fiddle the figures in a manner so likely to be rumbled?

Any one of these silly dodges, mean tricks and minor fiddles can be rationalised, justified or explained away. The elector notes them, files them half-forgotten in the unconscious memory, and moves on. Thornton Wilder describes the process vividly in The Bridge of San Luis Rey: “Carefully wrapped in understanding and forgiveness, it sank into her heart.” Only a contrary example can erase the memory of mean-spiritedness: time and forgetfulness never quite do.

When I argued the attractions of an early contest on this page in July, I thought there was one thumping advantage it offered Mr Brown, one reason the electorate would respect for going early to the country: that Mr Brown has not been elected either as Prime Minister or Labour leader, and wanted his own democratic mandate. For this there would be huge voter sympathy both for his courage and for his honour as a democrat.

But by playing around with people’s expectations, looking calculating, unconfident and cheap, he has come close to forfeiting such sympathy, and if he backs away now has plainly forfeited it for a 2008 election. There is a way to regain respect; this is his moment; and he must do it now.

Otherwise there’s a good Old Norse word Mr Brown risks attracting, and it’s “sly”. In the undergrowth of human endeavour, slyness is thought to offer some low advantage; but it is not thought to equip a beast for the primacy of the jungle; and it is not admired. Some would call an autumn election foolhardy, but nobody now would call it sly. If he thinks he could win, however, narrowly, then Gordon Brown has a chance to renew his premiership, while putting to flight a most unpleasant suspicion. If he retreats, he will reinforce it.

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