In his most trenchant report yet, Sir Philip Mawer, the Parliamentary Commissioner for Standards, said that the Deputy Prime Minister’s trip to Philip Anschutz’s ranch raised serious ethical problems that the Prime Minister needed to address.

“Might Mr Prescott’s acceptance of Mr Anschutz’s invitation reasonably be thought likely to influence his actions in the capacity of both a member and a minister? In my submission, yes,” he said.

Downing Street defied calls for an independent inquiry and threw a protective cloak around Tony Blair’s embattled deputy. A spokesman said the Prime Minister believed that there was “no problem” because the stay and gifts had been registered.

Yesterday Mr Prescott’s credibility was undermined further with the emergence of e-mails showing ministers ordering civil servants in 2003 to investigate whether they could fast-track a casino for the Dome owners. The inquiry came from Lord McIntosh of Haringey, who then had ministerial responsibilty for gambling.

Pressure on Mr Prescott was growing with many Labour MPs saying privately that he had become a damaging embarrassment to the party. One loyalist Labour MP said: “I don’t know of a Labour MP who thinks that John Prescott should still be deputy leader. But there is no mechanism for getting rid of Prescott and if you pull one string you could unravel the whole cardigan.”

At least seven ministers are believed to be canvassing support: Jack Straw, Harriet Harman, Patricia Hewitt, Hazel Blears, Alan Johnson, Peter Hain and David Miliband.

The Committee on Standards and Privileges released its response to Sir Philip’s report yesterday. It said: “We share the commissioner’s view, which Mr Prescott came to accept . . . that the nature of his relationship with Mr Anschutz meant that he was accepting hospitality from a source that might reasonably have been thought to influence ministerial action, the key test for recording hospitality received in a ministerial capacity in the Register of Members’ Interests.”

The committee, which acts as a disciplinary panel for MPs, said that, on the commissioner’s recommendation, it would not take action over breaches of parliamentary rules.

Sir Philip found that Mr Prescott registered the hospitality 11 months late, but suggested that the committee take no action because he had acted soon after The Times revealed details of the trip. Sir Philip found that Mr Prescott did not need to register the gifts with Parliament because he had done so with the department.

But the committee went beyond its remit to demand that Mr Blair never again bypass Sir John Bourn, appointed in March to investigate alleged breaches of ministerial rules.

Hugo Swire, the Shadow Culture Secretary, said: “It is simply untenable for Mr Blair not to launch an immediate investigation into the clear conflict of interest that has arisen. If he fails to do so, then any remaining shred of integrity that his Government has will be in tatters. There is no way that Mr Prescott can be left to run the country with this damning indictment hanging over him.”

The committee found that there were shortcomings concerning the recording of ministerial gifts within Mr Prescott’s department and they required urgent attention. Mr Prescott said that he fully accepted Sir Philip’s report.

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