Shadow Agriculture Minister Tim Yeo has written to Prime Minister Tony Blair seeking an inquiry into the matter, quoting Mr Blair's post-general election speech to MPs warning them they were "not here to enjoy the trappings of power but to do a job and uphold the highest standards in public life".

Dr Cunningham says he has done nothing wrong

Mr Yeo said that if Dr Cunningham was found to have acted improperly and disciplinary action were not taken then "failure to do so will merely confirm the impression that you [the prime minister] condone ministers enjoying a millionaire lifestyle, subsidised by the British tax-payer".

As well as calling on the prime minister to look into the reports, Mr Yeo will also call on the Commons Public Accounts Committee and the Agriculture Select Committee to investigate.

'Champagne Jack'

Mr Yeo said: "While British agriculture was going to the wall, Champagne Jack was wasting money on five-star hotels and parties for his cronies."

Jack Straw: Clear rules for ministers

Downing Street is dismissing the claims, first made by The Sunday Times, that Dr Cunningham, the former agriculture minister and now Cabinet Office minister, flew on Concorde and stayed at top hotels during the course of his duties.

A Cabinet Office spokesman added: "All travel by Dr Cunningham at MAFF and the Cabinet Office was within normal rules and approved by the department.

"Accommodation was fixed by the department and embassies concerned and was properly authorised."

But speaking on Sunday, Home Secretary Jack Straw said there could be an inquiry.