Bad news for voters still shell shocked from the chaotic events of May - it looks like the next election campaign has already begun. Gordon Brown's hint at the weekend that the next general election will be no later than 2009 is only the half of it. Labour constituencies are thought to be stepping up their candidate selection, ready for an election anytime in the next 18 months.

Even before he has entered No 10, Gordon Brown is laying the ground for what he hopes will be Labour's fourth election victory. Hence the widely-spun reports that he is about to revive the draconian proposals, rejected by the Commons two years ago, to extend the length of time terror suspects can be detained without charge from 28 days to 90 days.

There's some doubt about whether Mr Brown would go the whole distance on detention - it would mean innocent people serving the equivalent of a six-month sentence with remission - but the message is clear: Mr Brown will be as tough on terror as Tony Blair. He is not going to let the Tory leader, David Cameron, pose as the "heir to Blair".

The curious thing is that the Chancellor is already considered to be tougher on terror than the Tories, at least according to a poll in yesterday's Sunday Telegraph. The ICM survey suggested that voters thought Gordon Brown was a stronger leader than David Cameron, and that Mr Brown was more trusted on "hard" issues such as the economy, tax and terrorism. Meanwhile, the Tories are ahead on health, sleaze and education. This is an extraordinary reversal of the traditional roles for Britain's two major political parties. But the Brownites are confident that they can easily defeat the Tories on public services in an election campaign, so they are relaxed about the inversion.

Meanwhile, David Cameron, is in danger of losing the plot entirely. The row over his opposition to grammar schools (except the existing ones and, er, maybe some new ones), which led to the resignation of a shadow minister, Graham Brady, won't go away. Abandoning the sentimental attachment to grammars was intended to show how Mr Cameron had modernised the Conservative Party - but it has revealed the limits of his ability to discard Tory shibboleths.

Mr Cameron's attempts to be liberal, green, critical of business and sceptical about selection have provoked a much stronger reaction within his party than Tony Blair's mirror-image modernisation back in 1994. The Labour party went along with scrapping clause four, but the Tories clearly aren't ready to be the Polly Toynbee party.

The Tory leader is increasingly being criticised in the Tory press for his attempts to emulate the worst aspects of Blairite presentational politics, such as hiring of an Alastair Campbell clone - ex-News of the World editor Andy Coulson - as Tory communications chief on £275k. There's a feeling that David Cameron has been spun quite enough already. The public are not so easily taken in by gesture politics these days.

Mr Cameron got into trouble last year for cycling to the Commons, with his chauffeur-driven car following with his clothes and papers. Yesterday the Independent on Sunday revealed that his domestic environmental credentials are suspect, too. The wind turbine that the Tory leader erected on his Notting Hill home, with much media fanfare, has been taken down because the roof wasn't strong enough; his composter doesn't work because it keeps filling with water and a gardener grows Mr Cameron's prize-winning vegetables.

Of course, Mr Brown has also been indulging in a bit of his own greenwash - getting photographs taken of him doing his boxes on the London Underground. Yet he is a multi-home-owning politician who is no stranger to the shuttle lounge and who until recently was being ferried around in a 4x4 gas guzzler with smoked windows. However, Mr Brown's modest tastes and unflamboyant lifestyle give the Chancellor the edge over the well-heeled public schoolboy.

No doubt Mr Coulson will try to address the "posh" factor when he takes over as Mr Cameron's spin-doctor. He should also dump the curious claim that the Tories are "heirs to Blair". Mr Blair is a tainted brand. The assumption of Conservative election strategists has been that Gordon Brown will come from the left. They have inferred from the issues in Labour's deputy leadership contest that Mr Brown will revive things such as redistribution of wealth, the charitable status of private schools and an amnesty for illegal immigrants. I don't buy it, myself.

We can't assume Mr Brown will be more liberal than Tony Blair. He has a penchant for power and control and likes to use it, as he showed during his reign in the Treasury. Mr Brown will lock out the trade unions, promote privatisation in the health service, keep taxes low and make tough noises on terrorism. Gordon Brown will do anything - short of holidaying with Alex Salmond - to get Labour re-elected, and his focus on winning is awesome.

If necessary, Mr Brown will out-Tory the Tories, on the grounds that there is nowhere else for Labour voters to go (except in Scotland), now that Ming Campbell's Liberal Democrats are signed up to the Brown Project.

And he will hold the next election whenever he thinks the Tories are weakest. Indeed, if the Mr Cameron tailspin continues, it's possible that Gordon Brown might be tempted to revive the idea of a snap election as early as this autumn or next spring. About two years ago, when Labour was still comfortably ahead in the opinion polls, there was talk in the Chancellor's circles about the possibility of going to the country after six months in office, to counter the charge that Mr Brown had become Prime Minister without any election. The idea lapsed as Labour's lead lapsed - the Tories now have a comfortable opinion-poll lead over Labour: 37% - 32% in the latest ICM. However, that lead is not unassailable.

After a dynamic 100 days, in which he laid out his stall - affordable housing, parliamentary reform, troops out of Iraq - Mr Brown could seek a pretext to hold an immediate election, thus exploiting the Tories' leadership problems. With so many Conservative policies in flux - health, environment, education, Iraq - Mr Brown could shred the Tories in an intense three-week campaign building on his economic record and his reputation as a strong leader. If necessary he could enlist the support of Tony Blair to tell the voters that the only true heir to Mr Blair is Mr Brown.

No-one should underestimate the determination of the great clunking fist. Scotland's Returning Officers would do well to get their counting machines in order sooner rather than later.

Read Iain Macwhirter also in the Sunday Herald.