Blair's light at the end of the tunnel could be Brown's train

"Gordon Brown is still waiting." The words appeared on the screen at the close of The Deal, the recent Channel 4 drama about the arrangement under which Mr Brown gave Tony Blair a clear run for the Labour leadership in 1994.

The question on everyone's lips at Westminster yesterday was: "How long will Gordon have to wait before becoming Prime Minister?" There is a growing feeling among Labour MPs that a handover of power could be only months away following Mr Blair's decision to make university top-up fees an issue of confidence in his leadership. But ultra-Blairites remain convinced that the Prime Minister who has no reverse gear will find a fifth gear - and the oomph for a third term.

The Deal reminded us how the fates of New Labour's founding brothers have been intertwined since they entered Parliament in 1983. Mr Brown, the senior partner for 11 years, was in the wrong place when the music stopped in 1994, and Mr Blair became party leader.

Since then, Mr Blair has remained in the ascendancy. But now Labour MPs sense the balance of power is shifting back to Mr Brown. The body language of the two men during TV interviews on Sunday symbolised their contrasting fortunes. Mr Blair, in Nigeria for the Commonwealth summit, looked washed out, while Mr Brown seemed happy and relaxed on Sir David Frost's sofa.

The Chancellor was again in bouncy form yesterday, cracking jokes about "sleepless nights" after the birth of his son John. He painted an extremely rosy picture of the economy and slipped out, almost in passing, a £10bn increase in government borrowing this year.

He trailed the "big idea" for Labour's next election manifesto by announcing more money for children and child care. This is an example of what Mr Brown has dubbed "progressive universalism" - measures that help everyone but benefit the poorest most.

Mr Brown took pleasure in seeing his April forecast of growth for this year coming good, confounding the "doom-mongers". He predicted growth of between 3 per cent and 3.5 per cent for the next two years, which Britain has not enjoyed in consecutive years since the Lawson boom of the 1980s.

Yesterday, the Chancellor could legitimately put off difficult decisions on how to balance his books until another day. However, the spectre of further tax rises looms after the general election expected in 2005.

Although aides insist there is no "black hole" in his spending plans, the danger for the Chancellor is that he will still be at the Treasury when the music stops and taxes have to rise again. That could put a question mark over his economic record.

The Prime Minister shows no sign of wanting to give up. But his fate may no longer be in his own hands, and January could be a cruel month, with the Commons vote on top-up fees and Lord Hutton's report into the death of David Kelly.

Relations between the Prime Minister and the Chancellor have improved recently after their partnership hit its rockiest patch over the summer. The role of marriage guidance counsellor was played by the unlikely figure of Michael Howard. Perhaps their feuding could be afforded while Iain Duncan Smith was Tory leader, but Mr Howard's impressive start made the Prime Minister and the Chancellor realise they could not afford the luxury of squabbling. "They looked over the cliff and agreed they had to pull back," said one insider.

So Mr Brown rowed in behind Mr Blair's plans to inject more "choice" into public services, a long-running cause of friction between them. He also endorsed the Blair proposal to allow universities to charge top-up fees of up to £3,000 a year.

The Chancellor gets irritated when Blair allies complain that he slightly qualifies his support for the Prime Minister to remind the Labour Party that it can still put a cigarette paper between them. Asked on Sunday whether he supported variable fees, Mr Brown began his reply carefully: "Tony Blair has said that the variable fee is part of the system."

If Mr Blair survives his January ordeal and wins another election, he might well stand down after holding a euro referendum. But even if Mr Brown succeeded him, he might only have a couple of years at the head of a dying Labour administration. "Gordon's nightmare is that he becomes Prime Minister but never wins an election," one ally said. January may turn out to be an important month for Mr Brown too.