On the day after the Budget this year Alistair Darling’s daughter Anna texted him from South Africa, where she was travelling during a gap year. “Hey dad, is it true you’ve wrecked the economy?” she asked. “No,” the Chancellor drily replied.

What is surprising is that most people would agree with him. It is extraordinary that the man who has been in charge of the British economy during the worst recession for a century has emerged with his reputation intact, even enhanced.

While Norman Lamont’s public image was destroyed when he admitted singing in the bath on Black Wednesday and Hank Paulson ended his tenure as US Treasury Secretary as a symbol of failure, Mr Darling has somehow managed to strengthen his political position during the nation’s financial dark night of the soul. In Westminster he is widely seen as unsackable after the Prime Minister’s aborted attempt to replace him with Ed Balls and is now routinely mentioned as one of only a handful of Cabinet ministers who could, if he wanted to, depose Gordon Brown. His courtesy during curry-fuelled all nighters has won him the loyalty and affection of Treasury civil servants. Despite presiding over the near-collapse of the banking system and pumping billions of pounds of taxpayers’ money into the economy, he is still perceived in the City as a (relatively) safe pair of hands.

He has done it by standing up to Gordon Brown and refusing, by and large, to play politics with the economy. Tomorrow’s Pre-Budget Report will be the ultimate test of his ability to hold that line. For the Prime Minister, the statement is Labour’s big chance to create dividing lines with the Conservatives before the general election; for the Chancellor it is a moment to steady the markets by setting out a clear deficit reduction plan. Not surprisingly the difference of emphasis has caused tension between No 10 and No 11. “There are a number of rows going on,” one official closely involved in the discussions told me last week. “Gordon should have learnt by now that Alistair is not quite the pushover he thought he was. There'll be blood on the carpet over this PBR.”

The disagreements have been about individual measures but also about strategy and presentation. Mr Darling, whose great-uncle was a Tory MP and who was educated at public school, is less comfortable than Mr Brown with class war. “I don’t care whether David Cameron went to Eton or not,” he said on Sunday. No 10 is quite happy for the Pre-Budget Report to be seen as a package that will “soak the rich” to allow Mr Brown to position Labour as the party of ordinary people and the Tories as the champions of privilege. The Treasury hates the idea that this week’s statement could be seen as an attack on wealth and is keen to make clear that any action will be carefully targeted. A powerful alliance has formed between Lord Mandelson, a long-term admirer of the “filthy rich”, and Mr Darling. In strategy meetings preparing for the PBR, the Business Secretary has consistently sided with the Chancellor against the Prime Minister and Mr Balls, the Children’s Secretary, on everything from dealing with bonuses to tackling the deficit.

Mr Darling is not averse to a bit of banker-bashing — even before the credit crunch he once told me that boardrooms should apply the “next-door neighbour test” and consider whether they could justify high pay over the garden fence — but he is more worried about the long-term impact on the City than Mr Brown. The Chancellor has insisted that any windfall tax on bonuses should be a “surgical strike” applied for one year only. The Prime Minister would have preferred a more sustained aerial bombardment.

The Treasury also appears to have seen off calls to lower the level at which the new 50 per cent rate of tax will kick in from £150,000 to £100,000. On inheritance tax, Mr Darling is ready to freeze the threshold — but he is said to have resisted requests to reverse plans to make it easier for couples to pool their allowances. He has gained in confidence since the Pre-Budget Report that followed the election-that-never-was, when Mr Brown forced him to follow the Tories’ inheritance tax plans, causing his biggest political wobble. As one aide puts it: “Alistair won’t put politics before economics now.”

It is on proposals to reduce the deficit and cut spending that Mr Darling is most determined to hold his ground. In the run-up to successive Budgets and Pre-Budget Reports the Prime Minister has tried to persuade the Chancellor to massage the figures to present a more optimistic picture of the British economy, and this time is no exception. “Gordon wants everything to be as rosy as possible but Alistair thinks it’s more important to be honest,” one Treasury insider says.

This tension has been there right from the start — when Mr Darling said that Britain was facing the worst recession for 60 years, Mr Brown telephoned him to tell him the downturn would be over in six months — “I hope you’re right,” the Chancellor said. Of course the Prime Minister’s optimism was misplaced.

In recent weeks Mr Darling has refused to upgrade his growth forecasts. He has also resisted a new attempt from Downing Street to facilitate a campaign pitching Labour investment against Tory cuts. When Mr Balls let it be known that he had bid for an extra £2.6 billion for schools, the Chancellor slapped him down and made clear that the Treasury would not be publishing detailed spending plans. Instead, he wants to concentrate on finding savings to cut the deficit. For him, it is not enough to propose Whitehall efficiencies, the Government has to make real cuts — there could be more on public sector pay. “Alistair’s not going to play the role of Santa this week,” says an aide. Gordon would like to give the impression he is ready to fill voters’ stockings with goodies. But the truth is that there is no money at all to pay the elves.

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