At least 50 Labour MPs will be forced to quit at the next election over the Commons expenses scandal, a senior trade union leader predicted yesterday.
Paul Kenny, the general secretary of the GMB union – one of Labour's biggest financial backers – spoke out as a party "star chamber" began examining the allegations against four backbenchers.
Mr Kenny, whose union has two seats on Labour's ruling National Executive Committee, warned that Cabinet ministers should not be spared from possible action by the party. "You can't have one rule for backbenchers and another for people who are the political elite of government," he told the BBC.
"Where people have used the system to profit themselves, whether that be through excessive claims for personal items or through making vast amounts through 'flipping' their second and third homes, it is pretty clear that all of those people are going to have to be subject to intense scrutiny by the Labour Party."
Mr Kenny said he expected significant numbers of MPs from both main parties would have to stand down by the time of the next General Election.
"If that that is less than 20 per cent of the current number of MPs I will be quite shocked," he said.
"It will be well in excess of a hundred, I would have said. I think at least 50 from the two major parties and there will be a sprinkling of others."
Labour sources were privately dismissive of his claims. The Labour disciplinary panel, which contains three NEC members, is expected to deliberate into next month.
Yesterday it began considering the cases of three backbenchers – Margaret Moran, Elliot Morley and Ian Gibson. The case of a fourth Labour MP, David Chaytor, will be heard at a later date.
The party did not say whether any of the MPs concerned attended the hearings – Ms Moran earlier said she was staying away on grounds of ill- health.
A spokesman said: "The panel is currently in the process of gathering evidence from all parties concerned in these cases and the Labour Party will make a further announcement when it has come to its conclusions.
"All members of the panel agreed on the need for rapid and urgent action to reassure the public and Labour Party members, but the panel is also clear that all its investigations must be conducted in a fair and equitable manner in accordance with Labour Party rules."
Gordon Brown said last night: "We are going to clean up the political system. We are never again going to have a situation where MPs are put in this position, where they sign their own expenses and have to do it all on their own and getting into mistakes which then have to be corrected.
He added: "Any MPs that misbehave will be dealt with. Any MP who has to be disciplined as a result of what they have done will be disciplined.
"Any MP that cannot stand at the next election because of what they have done, we will take the action that is necessary."
Jack Straw, the Justice Secretary, said the mood in Cabinet was "very serious... recognising the concerns of the public" about expenses.
But ministers were also "determined to ensure that we back the Prime Minister in the action he proposes" against Labour MPs who broke the rules and cross-party efforts to reform the system.
He said: "I don't think there is a single member of the House of Commons that has not been shocked and saddened by what happened."