John Rentoul: 'Events' are moving in Cameron's favour

Gordon Brown should call an election this autumn. As the political season prepares to resume, the nature of the struggle ahead is becoming clearer. The Prime Minister is riding the wave of a successful transition, but what Labour people ought to be singing to themselves is their 1997 election theme tune with the words: "Things Can Only Get Worse".

Last week's shock development, that of David Cameron finally winning the support of The Sun, ought to be a warning to those who thought the Conservative machine was falling apart already. Not that The Sun has come out for Cameron yet – if anything it continues to lean to Brown – but it backed a speech the Tory leader gave last Wednesday. And, yes, we can point out the irony of a Conservative leader and a conservative newspaper uniting around a slogan, "Anarchy in the UK", that was minted by the Sex Pistols 30 years ago. But that postmodern alliance is terribly dangerous for Labour.

Not that yesterday's ICM poll was evidence of the threat to Brown, despite the way it was reported in some quarters as a dramatic narrowing of Labour's lead. In fact, Labour's five-point advantage was only one percentage point lower than in ICM's previous poll two weeks ago. But a more detailed analysis of the opinion polls suggests all kinds of reasons for Labour not to be too cheerful. First, it is worth noting that ICM found that Brown's accession has taken a big chunk out of "time for a change" sentiment. Last September 70 per cent of its respondents agreed that it was time for a change – yesterday that figure had dropped to 55 per cent. That means that an awful lot of people still think it is time for a change, after a transition to a new leader who used the word "change" in his speech on the threshold of 10 Downing Street eight times.

And a closer look at the nature of the "Brown Bounce" in the polls is revealing. Figures compiled by David Cowling at the BBC Political Research Unit suggest that Labour enjoyed a 10-point gain between April and July this year, from an average of 29 per cent to 39 per cent, which has continued through August. But my analysis of the figures is that Labour's new supporters came more from the Liberal Democrats, who lost four points, and from other parties, who lost three, not from the Conservatives, whose average rating slipped only three points.

That does not suggest a Tory meltdown. Far from it. Given that this Prime Minister can only be "the change" once, that 39 per cent could be the high water mark of the Brown tide.

For we go into the pre-conference political season with things starting to go David Cameron's way, as they were bound to at some point. Of course, one week's headlines about teenage killers and one good speech do not make a political strategy. Indeed, it was not even a very good speech. One Sunday commentator was particularly taken by the line: "I don't know who killed Rhys Jones. But I do know this: no child in this country should be riding around on a BMX bike with a gun shooting other children." That was possibly the worst sentence I have heard a politician deliver since Michael Howard invented "walking with a purpose". But what was so disappointing about the speech was the poor quality of its argument. For those of you who have not read the entire text, Cameron took the killing of 11-year-old Rhys in Croxteth as a rallying call for a different approach to crime. The parallel with the speech Tony Blair gave in Wellingborough in 1993 after the killing of James Bulger by two 10-year-olds was obvious, and has been much remarked. But the differences were perhaps more important.

Cameron's speech did one of the things that Blair was good at, namely identifying with a state of public anxiety. But it was less effective at remedies. Not that Blair was brilliant at that either – in the end the main policy of the 1997 manifesto on this subject was the promise to halve the time between arrest and sentencing for young offenders. That was achieved – eventually – although the system is still much too slow, and the main innovation since then has been anti-social behaviour orders, which may be necessary but they hardly address the causes of crime.

Blair believed there were things that the government could do to deal with the causes of crime. Cameron is doubtful. He waxed passionate about not putting up with it any more, and said that if people were serious about it, then, er, fathers should not run away from their responsibilities, parents should know where their children are, and magazines, movies and computer games should change our "culture". Well, Blair in opposition may have been sketchy, and Blair in government may have been patchy, but this is pathetic.

Unfortunately, it does not really matter how low my opinion is of Cameron's policies or lack of them, he is on to a cluster of issues on which Labour is bound to be defensive. Crime; the free movement of people, including criminals such as Learco Chindamo, around the European Union; indiscipline in schools; bureaucratic sclerosis in the police.

If those are the issues that dominate the resumption of hand-to-hand politics, then Brown has got a fight on his hands. It is astonishing how quickly politics can turn around. Before the summer I had a discussion with Michael Gove, newly promoted to shadow Children's Secretary. I teased him about The Spectator naming him as a possible replacement if the grumbling against Cameron's leadership turned into a serious revolt. He protested so effusively and excessively that I thought for a moment that there might really be something in it. And when, amid people on sunloungers reading Harry Potter in French and German, I read of strange happenings back home on Planet Redwood, where the Vulcan was proposing massive tax cuts, I thought the Tory collapse scenario might not be fanciful after all.

But back home the skies were dark and the headlines grim. The suddenness with which the political weather can change is a warning to Brown. Obviously, events can move in his favour. But overall "events" are more likely to cut against the governing party.

If Brown can sustain Labour's average 39 per cent rating in the opinion polls this autumn, it may be the best he will get. Given that the polls have in the past four election campaigns overstated Labour's support by an average of five points, that may not seem like a very strong position. But on past evidence, it is enough to win a small working majority. It may not be great, but it may be as good as it gets.

Gordon should go for an election in October. But he will not, because it risks throwing away the prize he has only just won. He may come to regret it.

John Rentoul is the chief political commentator for The Independent on Sunday.