Conservative MEPs gave warning yesterday of a “timebomb” of further damaging disclosures about their expenses when they are forced to apply Westminster-style transparency.

Some complained about the levels of openness being demanded by Hugh Thomas, the party’s head of compliance, who was sent to Brussels after the resignation of Giles Chichester, the Tory group leader, for channelling £445,000 to a company of which he was a paid director.

With half a dozen MEPs already facing questions over their use of EU expenses, The Times understands that bitter infighting broke out at the MEPs’ private meeting with Mr Thomas yesterday.

Some have blamed a think-tank with close links to William Hague, the Shadow Foreign Secretary, for fuelling a witch-hunt. Older hands fear that damaging disclosures are being encouraged to prepare for the sackings of several MEPs seen as too comfortable in Brussels and not sufficiently Eurosceptic. One MEP said: “I am hearing that they want to remove the whip from two people, which will then be seen as a strong response to all the revelations.”

David Cameron is understood to be angry that the Conservative lead over Labour in opinion polls could be jeopardised by the revival of allegations of Tory sleaze against his MEPs.

Den Dover, the former Chief Whip in Brussels, lost his job last week after the disclosure that he had handed £758,000 in staffing allowances over seven years to a company run by his wife and daughter. Sir Robert Atkins, MEP, has denied any wrongdoing in using parliamentary expenses to travel to the US at the time of his son’s wedding. He said that he went on an official visit at the invitation of the Republican Party during mid-term elections. At yesterday’s meeting, a senior MEP warned Mr Thomas that he would unleash a timebomb of disclosures that would further damage the image of the party. Tory MEPs complained that they were being unfairly exposed for taking advantage of the European Parliament’s generous allowances without breaking the rules when other parties demanded less openness.

There were also accusations that details of expenses were being pushed by the Eurosceptic Open Europe think-tank, whose director Neil O’Brien is understood to write speeches for Mr Hague. Mr O’Brien said that there were allegations of unacceptable use of expenses against MEPs from all the main parties. He added: “There will be a huge premium for whichever party leader can be shown to take action against sleaze in Brussels.”

Meanwhile, Sir Christopher Kelly, the chairman of the Committee on Standards in Public Life, kept up pressure on MPs at Westminster by questioning whether they should ever pay their children and parents out of parliamentary expenses. He said that the practice of MPs using allowances to hire spouses was “a pretty unusual arrangement where public money is concerned”. But Sir Christopher told the BBC: “I find that argument more difficult to sustain when it extends to people’s mothers or children, particularly when there is no evidence that those people are undertaking any work for the pay they receive.”

The Tories were accused by rival parties yesterday of trying to create a smokescreen to divert attention from their own troubles by making “scatter-gun” allegations against other MEPs. A day after questions were asked about personal donations worth £57,000 by Mr Dover to his party since 2001, and a donation of £1,200 from the company that handles his parliamentary staffing allowance, a list was circulated from Tory sources of Liberal Democrat MEPs who have donated a total of £86,000 to their party over the past seven years.

The Tories made inquiries after Chris Davies, a Lib Dem MEP, admitted that he had donated the surplus he made from European Parliament travel expenses, which reimburses the full cost of an open ticket even if the MEP takes a cheaper alternative.

Mr Davies said: “The Tories are trying to capitalise on a question I answered poorly on Newsnight.Let me make clear that I do not make donations to my political party out of expenses intended to meet the cost of performing my parliamentary duties in any way.”

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