Senior Cabinet ministers desperately closed ranks behind Gordon Brown last night after a dark week for the Prime Minister ended with Charles Clarke saying that recent events made him ashamed to be a Labour MP.

Alan Johnson, the Health Secretary, who Cabinet ministers believe will emerge as a leadership candidate if Labour loses the general election, declared that he had become a greater admirer of Mr Brown “the longer I spend looking at him in action close up”. Interviewed by The Times, Mr Johnson admitted that he had never been “secretary of the Brown fan club” but said he believed that Mr Brown was “doing the right thing”.

Harriet Harman, the deputy Labour leader, demanded unity under Mr Brown. Speaking in Scotland she said that Labour’s future as a government and party depended on its whole team working together, mapping a way forward and keeping the Tories out.

Senior ministers believe that there is little or no chance of Mr Brown going before the election, expected on May 6 next year. But there is growing backing for Mr Johnson to emerge as the unity candidate if Labour loses.

In the interview Mr Johnson suggested that Labour must not use the recession as an excuse to veer to the left and hinted that he believed that the new 50p tax rate should be temporary. He did not rule himself out as a future leadership candidate.

But Mr Clarke, the former Home Secretary, added to the immediate pressure on Mr Brown since his defeat over the Gurkhas and the row on MPs’ expenses by saying that recent events have made him “ashamed”.

Mr Clarke told the BBC he had “worked half my life to get Labour into a position where it could be a good government and I do see that fading away”.

Another former Home Secretary, David Blunkett, warned of a “catastrophic” collapse in trust and urged Mr Brown to regain the political initiative.

Mr Clarke said that Labour’s performance had to “improve dramatically”. He urged the Prime Minister to ensure that MPs’ expenses were sorted out “on an all-party basis rather than a party advantage basis” and to ensure “the kinds of political conduct symbolised by Damian McBride \ at the core of government are driven out”.

Asked how he felt to see the party apparently falling apart, he said: “It’s absolutely terrible. There have been things that have been done recently which have made me feel ashamed to be a Labour Member of Parliament, which was something I never ever wanted to be.

“I worked over my whole political life to get Labour into a position where it could be a good government and I do see that fading away . . . And it feels absolutely appalling. So what do you do? You have to refocus on what the steps we have to take to improve our performance and improve our activity — and that has to be the No 1 thing.”

Asked if a change of leadership was the answer, he said: “I don’t think so. I very much expect Gordon to be leading us into the next general election.

“Obviously Gordon will think about his own position as he rightly should, but I don’t think there’s a lot of movement around whether Gordon should be moved but there’s a lot around saying Gordon has to improve his performance.”

Frank Field, a former minister and another persistent backbench critic of Mr Brown, has said that Labour has “one last chance” to consider replacing him, arguing that the “balloon might go up” when the results of European and local elections are known on June 4. “I would then hope we had a new leader and, in the meantime, we get on with showing we can perform well as a government with our programme actually laying the basis for our manifesto commitments,” he told Public Servant magazine.

Mr Field said that the McBride e-mail scandal had left Labour MPs “staring into the abyss” and insisted that there would be time to install a new leader before a possible general election next year.

Bob Marshall-Andrews, the Labour MP for Medway, said that the party would inevitably lose the next election. The expenses debate procedures were a debacle, he said. “Having made a fool of himself on YouTube, the Prime Minister tried to get out of it by making a fool of the House of Commons.”

Ken Livingstone, the former Mayor of London, said: “All the party is united in thinking we are doomed.”

The Prime Minister’s official spokesman dismissed claims that Mr Brown had stopped listening to colleagues and had been damaged by this week’s events. He said that Mr Brown was continuing to focus on the important issues facing the country such as swine flu, policy in Afghanistan and Pakistan and dealing with the economic slowdown. He added: “Once you poke through the froth on expenses we achieved more in one day on the issue than in the last 20 or 30 years.”

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