Andrew Grice: By wielding the dagger, has Mr Brown ensured he cannot wear the crown?

The most likely scenario is still that Brown eventually succeeds Blair, because he remains head and shoulders above his rivals

When Tony Blair and five cabinet ministers flew by helicopter to Gloucestershire on Monday for the funeral of their colleague Lord Williams, one of them quipped: "Well, if we crash, Gordon will get it." The ministers laughed, but the statement rang true, since the passengers included potential rivals in Charles Clarke, Jack Straw and Peter Hain.

What the ministers did not know was that, back in Bournemouth, Gordon Brown was launching an unmistakable pitch to inherit Mr Blair's crown in his conference speech. Sensing rightly that the Prime Minister was in trouble, the Chancellor reminded us that he was the leader-in-waiting - already an undisputed fact.

When Mr Blair heard about Mr Brown's appeal to traditional Labour, he was surprised and irritated. The two co-founders of New Labour have had their differences since 1997, notably over the euro and the role of the market in public services. Yet for all the tension, and the Chancellor's undoubted ambition to succeed his long-time ally, Mr Brown had never broken cover in public until Monday. So his address was a landmark. As Mr Blair and his advisers finalised his speech to be made the next day, they judged that Mr Brown had made the Prime Minister's task even harder. But Mr Blair rose to the challenge, as he usually does, helped by an unexpectedly warm welcome when he took the podium.

Many Labour members do not love Mr Blair or his "New Labour" project, feeling instinctively more comfortable with Mr Brown's "Labour" prospectus. Yet many conference delegates were unhappy at Tuesday morning's newspaper headlines about the Chancellor's leadership pitch, and rallied behind the Prime Minister. "We were very worried by Gordon's speech, but in the end it turned out to be a help rather than a hindrance," one Downing Street aide said. "It was intended to weaken Tony, but it strengthened him."

Even close Brown allies admit that his speech backfired. The problem was compounded by press photographs showing him not clapping while other cabinet ministers applauded Mr Blair's address. In fact, Mr Brown did clap, and stopped doing so only for a few fatal seconds. But the pictures nonetheless displayed his true ambition. The Brownites insist that their man was not plotting, merely stroking the party. They say he is damned whatever he does, asking: "Was he supposed to make, a boring speech?"

Yet cabinet ministers were puzzled by Mr Brown's apparent misjudgment. The talk of the town in Bournemouth was that he had forgotten the lesson of Michael Heseltine's challenge to Margaret Thatcher: he who wields the dagger does not wear the crown. "Gordon has done himself a lot of damage," said one minister with a foot in both Blair and Brown camps. A Blairite cabinet member said: "Gordon is brilliant - but impossible."

Where this leaves the Blair-Brown relationship is not yet clear. But it has undoubtedly been changed by this week's dramatic events. There is a fresh round of fanciful talk of Mr Brown being offered the Foreign Office, so that Mr Blair can move ahead on the euro and public services. But I don't believe it, especially as Mr Brown would almost certainly turn it down and go to the backbenches. The most likely scenario is that Mr Brown goes back into his shell, awaits events, and eventually succeeds Mr Blair, because despite this week's turn of events he remains head and shoulders above his rivals.

He might have a long wait. Mr Blair left Bournemouth yesterday in a stronger position than he arrived. The conference showed he is still respected by many in his party, even if he has failed to turn New Labour from a clique at the top of the party into a mass movement. Despite their grave misgivings about the Iraq war, many Labour folk think it is time to move on.

Mr Blair still has a lot of repair work to do with Labour MPs, who feel neglected and unloved. We can expect a charm and "listening" offensive when Parliament returns later this month. Mr Blair can ignore a vote lost on foundation hospitals at the party conference, but he needs Parliament to support the plan - and university top up-fees.

The defeat on health policy, largely at the hands of the big trade unions, has provoked an intense debate on the Labour-union link. The problem, recognised by senior figures around Mr Blair, is that the new breed of union leaders - and especially the "big four" who met ahead of the conference to co-ordinate their strategy - are going to be around for a long time.

There will be pressure to revive the idea of changing Labour rules to prevent union barons casting their block votes in one direction at the party's annual conference, rather than splitting them to reflect the differing views within the union. If union block votes could be split in this way, instead of cast in the old monolithic way as has always been done, then it would reflect much more fairly what officials around Mr Blair believe is the reality. And that is that that union leaders are not only increasingly out of touch with the wider public - they are also out of touch, at least on issues of public service and social policy, with their own members.

The death of the block vote was pronounced years ago, and so Mr Blair may want to complete this piece of unfinished business. But divorce is not on the cards yet; like Mr Blair and Mr Brown, the party and unions still need each other. In particular, the party has to be careful it does not cut off what, unless and until it converts to state funding, as it may do in its next election manifesto, is a vital source of cash.

The comfort for the Labour leadership, however, is that the role of the unions in forcing a defeat for Mr Blair is in stark contrast to that of the constituency parties, who backed the pro-government motion - one which anyway set limits on use of the private sector in the NHS as well endorsing foundation hospitals - by a majority of about two to one. That makes it more difficult for the unions to argue that their block votes are representative of party opinion.

The fact that officials close to Mr Blair have been robust in highlighting what they see as the obstructive role of the unions is itself a sign that Mr Blair feels he has emerged from the conference with his leadership strengthened. There is no doubt something in the charge that the use of the conference rules to limit the number of emergency motions meant that what could have been a damaging vote on Iraq was avoided. But ironically, the unions themselves played a part by confining their motions to domestic issues. Which cannot fail to be another source of satisfaction to the leadership.

The relationship between Brown and Blair remains the most volatile and unpredictable factor in British politics. There have been moments before when each man has been strengthened at the expense of the other. But this was the most difficult conference Mr Blair has yet faced. He could not afford to fail. And for all the resounding cheers that greeted Mr Brown's speech on Monday, this was a better week for the Prime Minister than the Chancellor.

a.grice@independent.co.uk