John Rentoul: Gordon Brown has reinvented himself - now he has to persuade the left to follow

The Chancellor is engaged in an offensive as subtle as the D-Day landings to wrap himself in the flag

The lamentations and the gnashing of teeth have begun. What is the point of Gordon Brown, goes the cry, if he is just going to be Blair Mark II? It has come to something when the fact that the Chancellor supports his Government's policies is considered to be a news story.

It is not even as if his tactic is new - the tactic of allowing people to think he might share the liberal left's doubts about the Prime Minister before suddenly declaring his carefully worded loyalty just before a crunch Commons vote. Brown did it just before the vote on the Iraq war in March 2003 and the vote on tuition fees in January 2004, as well as the votes on identity cards, and the glorification of terrorism last week.

More unusually, perhaps, he has done it on the vote on the schools Bill - a Bill that has not even been published, and on which the big vote is not expected until the middle of next month. You can be sure that if the Chancellor announces that he supports his Government's policy more than 10 days before the four tellers line up to do their "Ayes to the right" cabaret routine, something is up.

What is up, in this case, is that the vote on the schools Bill is different in importance and in kind from most of the votes that are periodically described as critical for the Government. As one minister put it to me last week, this is the point around which "all the regime-changers are going to congregate".

Last month's defeat, which tightened up the definition of religious hatred, was a mere scrape - a successful parliamentary ambush by the opposition whips which incidentally improved the law but which had no real implications for the Prime Minister. Last week's votes on the Identity Cards and Terrorism Bills were never going to be chances to bring Tony Blair down - although it is worth digressing a moment to explain why.

The easiest way to understand this point is to look at last Friday's newspapers, almost all of which contained a photograph that is already well on the way to becoming iconic (that is to say, quite well known). It featured the Chancellor of the Exchequer looking as if he were on his way to a fancy dress party with a Battle of Britain theme. In fact he was on his way by helicopter to a Royal Navy frigate moored off the Isle of Wight, which was to provide a suitable backdrop - shades of President Bush declaring Mission Accomplished on an aircraft carrier - to his announcement of a 3 per cent pay rise for the armed forces. (Including, a nice touch this, slightly more for the lower ranks.)

The point being that Brown is engaged in an offensive as subtle as the D-Day landings to wrap himself in the flag - to proclaim that, as Prime Minister, he will take no chances with national security. Hence the idea that he would encourage the regime-changers on the Labour back benches to vote against the Government on either identity cards or terrorism is ridiculous. If there are circumstances in which a defeat for legislation identified with Blair would be in his interest, they were not last week's.

Nor would a big Labour rebellion against the schools Bill be in his interest. Schools reform is not such a symbolic issue for the wider electorate. Most people, who do not have strong views about education, have next to no idea what the White Paper is about. Yet most people who are in the Labour Party do have strong views about education and hate the White Paper almost regardless of what it says.

At last! After 12 years of the compromises necessary to gain and retain power, a short cut to socialism with no serious electoral consequences! All Labour MPs have to do is vote down the Bill, get Gordon in and - well, that is where the argument runs out of logical connections, but a quick medley of "The Red Flag", "Jerusalem" and the Swedish national anthem and you get the drift.

Trust a Tory to spoil the fun. The reason that the short cut is blocked is because David Cameron has promised that the Conservatives will support the schools Bill, so long as it moves "an iota" towards greater autonomy for schools. The Bill will, therefore, pass. Blair will not be defeated. The left can sneer all it likes about Ramsay MacBlair and having to rely on the Tories to get his flagship legislation through, but that is a symptom of their powerlessness, not Blair's weakness.

Brown knows that, which is why he has come out so early to back the Bill. It is possible that the number of Labour MPs voting against it will be kept below 40 (the exact figure required for Blair to say he did not need Tory help is complicated by the Northern Irish). But Brown knows that it is the Labour Party - and him - that will suffer if the rebellion is greater.

Blair's reputation might suffer if bitter party division is part of his legacy, but it is Brown who has to face the voters in 2009. It is time for the Chancellor, therefore, to go beyond his usual tactic of waiting for Blair to do all the ideological heavy lifting and then simply repeat the arguments that work best. He needs to get into the debate and help the Prime Minister to dispel the myths that are so damaging to both of them.

The big myth that is kept alive by an opportunist alliance of left and right is the story of Blair reinventing the Tory wheel. Peter Lilley, the Tory former cabinet minister, in a Bow Group pamphlet, Tony, Duke of York, calls on Tories to support Labour's reforms because they are essentially Conservative policies.

It sounds plausible. Labour abolished GP fundholding and an internal market in the NHS, only to introduce practice-based commissioning and an internal market. Labour abolished grant-maintained schools that were independent of local education authorities, only to introduce trust schools that are "independent" state schools. It is plausible, but it is utter nonsense. It was exposed when Blair welcomed Cameron's support for the schools Bill and then drew a dividing line over selection.

The Lilley-Labour left myth confuses ends and means. So many on the left are so suspicious of choice, markets, devolution and diversity that, even when they are used to pursue egalitarian aims, they allow the Tories to confuse them. The point about both grant-maintained schools and GP fundholding was that some schools and some GPs were better-funded than others. Trust school status and Labour's market reforms in the NHS are open to everyone on the basis of equal - and increased - funding.

Brown has never been clear about this argument. That is the real reason why some of his supporters are parading their disappointment. They can see the logic of posing in goggles as the patriotic defender of national security, but they are terrified that, by backing the schools Bill, he will force them to give up on their daydream of a short cut to socialism. It is his duty to wake them up.

The writer is chief political commentator for The Independent on Sunday

j.rentoul@independent.co.uk