The revelation, which was seen as further weakening the Prime Minister’s grip on power, means that even if he wins the next election the clock would be ticking on his premiership the moment he walked back into No 10.

The labourhome.org poll also found that the only minister less popular than Mr Brown is Chancellor Alistair Darling.

Foreign Secretary David Miliband – tipped as a possible successor to Mr Brown – scored better, with Health Secretary Alan Johnson top.

Another opinion poll yesterday revealed how little the British public now likes the PM, with Tory support at its highest level since David Cameron became leader three years ago.

The BPIX poll showed Labour trailing the Conservatives by 23 points, with support of 26 per cent compared with 49 per cent for the Tories.

Forty-four per cent said Mr Brown should resign immediately, while 85 per cent said he had performed worse than expected since becoming leader.

In contrast, 55 per cent said Mr Cameron had done better than they expected.

Half of those polled thought Mr Cameron was charismatic, against only three per cent for Mr Brown.

The Prime Minister is also viewed as arrogant, untrustworthy and money-grabbing – with more than four in 10 saying he would be the last of the three main party leaders to pay back a £20 loan.

Only one in 10 says Mr Brown represents change, against four in 10 for Mr Cameron.

The Tory leader is also seen as more “caring” by a proportion of nearly two to one, and is also considered to be a stronger leader – a quality once considered the preserve of “clunking fist” Mr Brown.

Many of the answers showed a massive turnaround since autumn last year when Mr Brown blew much public trust by hinting he was about to call an election before pulling back at the last minute.

A Tory spokesman said: “Long ago Gordon Brown lost the country’s support. Now his rank and file are deserting him in droves. The UK desperately needs a change.”