The Week in Politics: How can Blair and Brown scratch their seven-year itch?

Tony Blair and Gordon Brown both managed to upset the trade unions when they travelled to Brighton this week for the TUC conference. In the hall, the reaction to Mr Brown's tough message was lukewarm at best; when he sat down, the applause lasted about 20 seconds.

Suddenly, the big unions seem to regard the Chancellor as no better than the Prime Minister; they are blaming job losses in manufacturing on his economic strategy. Surely, this was not the same man who had schmoozed them so brilliantly at his regular receptions at No 11? If, by some unexpected twist of fate, Mr Brown fails to become Labour leader, never will so many canapés have been eaten in vain.

At least Mr Brown's message was open and up front. In contrast, Mr Blair addressed the TUC general council's private dinner, and got himself in a pickle. Labour aides briefed the press in advance that he would deliver a stern warning to the unions, saying the idea of a left-wing government was "the abiding delusion of 100 years of our party". The only trouble was that he didn't say it. Indeed, my union spies at the dinner say Mr Blair was surprisingly emollient towards the brothers. But he managed to upset them when they learnt that, for public consumption at least, he had attacked them. So much for the end of spin.

The differing approaches of the Prime Minister and the Chancellor to the trips to Brighton got me thinking about the most fascinating and pivotal relationship in British politics, one I have now watched from a ringside seat for 20 years.

With Mr Blair in his most difficult patch since winning power, it is hardly surprising that shares in Mr Brown have been rising. After Alan Milburn's resignation from the Cabinet in June, the Chancellor's main rival for the leadership had gone.

Whatever the two men discussed in 1994 at the Granita restaurant in Islington the tensions between them about "the succession" have never gone away. Some Blair aides attribute a recent cooling in relations between the two men to a "seven-year itch" - a belief in Mr Brown's mind that Mr Blair gave the impression over dinner that he would hand over the reins to his New Labour soulmate by now. The Blairites insist, of course, that no such promise was made, saying that Mr Blair may have uttered words to the effect that he would not be Prime Minister for ever.

The recent froideur is unlikely to surface in public. Both men know how damaging are reports of splits between No 10 and No 11. Mr Brown included five flattering references to Mr Blair in his TUC speech, knowing he would have been accused of disloyalty if he had not. But it seems to me that the two most powerful men in British politics have diverged sharply on the way forward. Both would argue they want to be "radical" but they have very different visions. For Mr Blair, it means more bold reforms on public services and calling a euro referendum as soon as possible, even though this is now likely to be after the next general election. He regards Mr Brown as a roadblock on both fronts. Mr Brown filleted Mr Milburn's plans for foundation hospitals and pushed a euro referendum on to the backburner.

The frustration in the Blair camp is so intense that some insiders even speculate that the Prime Minister no longer wants the Chancellor to succeed him. This is heavy stuff. But there are no smoke signals without fire, and the Blairites are pretty miffed with the guy next door. They also accuse him of keeping his head below the parapet when Mr Blair is in trouble.

For Mr Brown's part, "radical" means galvanising a sullen Labour Party by launching a big push to tackle the poverty and inequality that still scar Britain. He wants Labour to focus on its successes, notably on the economy, in the run-up to the election, rather than the Blairite mantra of "delivery" and "transforming" public services, which only raises wild expectations that cannot be fulfilled.

An unflattering portrait of the Prime Minister emerges from the Brown camp: a man lacking vision and direction, who offers a pale shadow of socialism that is little better than One Nation Toryism.

How can the Prime Minister and Chancellor resolve these differences? Surely they sink and swim together, and still need each other. They remind me of the elderly married couple in Francois Mauriac's novel The Viper's Tangle, who achieve a reconciliation after years of separate lives under the same roof. In the husband's words: "While appearing to hate each other, we had arrived at the same point."

a.grice@independent.co.uk