ALISTAIR DARLING’S career was hanging by a thread last night after Gordon Brown refused to back his Chancellor to survive damaging revelations about his expenses.

In an interview, the Prime Minister failed to guarantee that Mr Darling, or Communities Secretary Hazel Blears, would still be in their jobs in a week’s time.

Mr Brown said of the beleaguered pair: “They are doing a good job, but I am not going to make any predictions about anything that is going to happen in the next week.”

The comment, which came after Mr Darling agreed to pay back about £700 he claimed for running a flat he rented out, is astounding because a prime minister normally backs his Chancellor to the hilt, if only to satisfy the financial markets.

It also appeared to confirm a looming Cabinet reshuffle after Labour’s expected drubbing in this week’s local and European elections, possibly as early as Friday.

The shake-up is expected to include the sackings of a number of senior ministers at the centre of expenses allegations, including Ms Blears, Home Secretary Jacqui Smith – and, perhaps, Mr Darling.

The Chancellor originally described yesterday’s Daily Telegraph allegation that he broke parliamentary rules by claiming second-home allowances on two properties simultaneously as “simply untrue”.

The paper reported that, in July 2007, he claimed £1,004 for a service charge on his south London flat for the following six-month period – during which he moved into the grace-and-favour residence of No 11 Downing Street.

But, after Mr Brown said there was “no foundation” to the allegations, Mr Darling backtracked by announcing he would repay about £700, to cover the charge from September 2007, when he moved into No 11.

It was a further blow to a reputation battered by allegations that he “flipped” his second home to maximise claims and charged accountancy fees to the taxpayer.

Mr Brown is believed to be considering replacing Mr Darling with Children’s Secretary Ed Balls, his closest ally and one-time economic advisor.

Meanwhile, Ms Blears is vulnerable after the Prime Minister described her failure to pay capital gains tax on the sale of an expenses-funded flat as “completely unacceptable”.

The £13,332 was later repaid.

Mr Darling said: “The allegation I claimed for two houses at the same time is untrue.

However, because the service charge covered the period beyond September until December, I will repay the service charge from September to December.”

Later, asked in TV interviews if he expected to be axed, the Chancellor said: “It’s up to the Prime Minister.

He has got to decide the team he wants to be in the next Government.

“That’s entirely a matter for him.”

That apparently resigned attitude was in contrast to last summer when Mr Darling reacted to criticism by predicting that his job was secure.

The Liberal Democrats called for Mr Darling to be sacked, because he had been “caught with his fingers in the till”, while the Conservatives accused Mr Brown of “dithering” over his position.

Hinting that he may yet lose his position, Mr Darling said: “Until there is a reshuffle I would like to get on with the job I am here to do and I’m pretty focused on that but it is for Gordon Brown to decide.”