Europe Correspondent Angus Roxburgh: "The nuclear option"

The surprise shift was signalled on Thursday by Pauline Green, leader of the Socialist group in the European Parliament, after weeks in which centre-left MEPs have warned against deploying the "nuclear" option.

The news came as the row over alleged fraud and mismanagement within the commission escalated. Mrs Green said that whatever the outcome of the censure vote, it was vital to resolve the crisis quickly to avoid paralysis in Brussels.

UK Labour MEP Pauline Green signalled her party may switch sides on the issue

But she acknowledged that if the present 20-strong commission is sacked, the momentum will be lost on key financial and farm reform programmes and the EU expansion talks with eastern European countries.

She also agreed that the gathering storm would do nothing to improve the EU's image in the UK at a time when the government is seeking to build support for joining the single European currency.

Whistleblower suspended

The commission official responsible for bringing a simmering dispute to the boil later claimed whistleblowing activities had put him in danger.

Paul Van Buitenen, a member of the European Commission's financial control unit, passed confidential details of anti-fraud investigations to MEPs to expose what he said was a cover-up of fraud and managerial incompetence which has cost EU taxpayers millions of pounds.

He has been suspended and faces dismissal proceedings, but insisted: "I did what I felt I had to do."

The European Parliament has the power to get rid of the entire 20-strong commission

Mr Van Buitenen moved out of his house in Brussels after being warned by colleagues on the telephone that he might be a target because of his actions. But he refused to say where the threat came from and has since returned to the family home.

Meanwhile Mrs Green, the Labour MEP for London North, attacked Tory demands that six EU commissioners should resign to avoid the risk of a comprehensive censure vote which would force resignations en masse.

She pointed out that MEPs had no power to target individuals - and that the "rumours" of wrongdoing had not yet been proven. "If and when they are proven against particular commissioners, then I will be behind any moves for them to resign," she insisted.

She rejected any comparison with the situation of former Trade Secretary Peter Mandelson, who resigned from the government because of the appearance of wrongdoing. Mrs Green insisted: "That was different. Mr Mandelson admitted he had made an error of judgement. The commissioners in this case do not. In fact they deny any wrongdoing at all."

Centre-left targeted

Commissioner Emma Bonino, from the centre-left, is one of those being targeted by the Tories

Tories want centre-left commissioners Emma Bonino, Edith Cresson, Anita Gradin, Manuel Marin, Christos Papoutsis and the man in charge of the EU budget, Erkki Liikanen, to go. Neither of the UK's two commissioners, Neil Kinnock and Sir Leon Brittan, are implicated in the crisis.

The allegations against the six commissioners - all hotly denied with a writ from Edith Cresson against a French newspaper - range from presiding over uncontrolled departments in which multi-million pound sums have been misused or abused, to nepotism.

But Mrs Green said: "Some people are using this issue of alleged fraud and mismanagement for party political purposes."

And the bitter recriminations continued when the Green group of MEPs in Strasbourg issued a statement declaring: "The Socialist group and its leader Mrs Green are becoming more and more nervous before the censure vote.