Sacking or demoting Alistair Darling would not begin to solve Gordon Brown’s acute political problems and could make them worse. But Mr Darling’s position as Chancellor is not secure. He could still be moved in a reshuffle expected after the end of the Labour conference in three weeks’ time. This is now an open question.

What changed over the weekend is that the simmering tensions between 10 Downing Street and the Treasury since last autumn over Northern Rock and the 10p tax debacle came out into the open. Mr Brown’s advisers did not disguise their, and his, annoyance with the Hebridean candour that the Chancellor showed in his Guardian interview. This was seen as making it much harder for Mr Brown to promote and sell his economic (and, of course, political) recovery plan.

Relations between a prime minister and chancellor are central to the harmony, unity and political health of any government. Their perspectives differ, and strains are hard to avoid at some stage, particularly when the prime minister takes such a close interest in the economy, as Mr Brown does.

There are three key tests. First, has trust irretrievably broken down between Mr Brown and Mr Darling? Probably not yet, despite growing strains. Second, has the Chancellor lost the confidence of the public, business and the City? That is Mr Darling’s biggest vulnerability, to judge by comments yesterday.

Third, is there a credible alternative? No chancellor is irreplaceable. But there are no obviously strong successors now: Ed Balls has the economic experience, but has not yet shown the necessary political wisdom, tact and public appeal; while David Miliband would be seen as a potential rival to Mr Brown.

Much more likely is that Mr Darling would be seen as the fall-guy taking the rap for mistakes made by Mr Brown when he was Chancellor or during his subsequent Downing Street interference.

The latest Populus poll for The Times, undertaken over the weekend, underlines the depth of voter disillusionment with Labour and Mr Brown — going well beyond who is chancellor. Voting intention figures are unchanged since late July but that is no comfort for Mr Brown.

Labour has now been below 30 per cent in all but two of 38 published polls since mid-May and has averaged 26 per cent for three consecutive months. The Conservatives have averaged 45 to 46 per cent over the same period. According to Populus, 51 per cent of those who voted Labour in 2005 say they would do so in a general election now, while 19 per cent would vote Tory. But 83 per cent of Tory voters in 2005 would do so again now.

David Cameron and George Osborne have retained a big lead over Mr Brown and Mr Darling on being trusted to handle economic troubles.

Most worrying of all for Mr Brown, before the launch of the first stage of his economic recovery plan today, is that voters are highly sceptical of the impact of the rumoured measures. While a big majority support action to help housebuyers and to help poor families with their fuel bills, two thirds to three quarters believe it will make little or no difference to the economic situation affecting them, and their families.

Most voters have given up on the Brown Government, and little it can say or do is likely to shift that hostility, whether or not Mr Darling stays.

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