The Deputy Prime Minister and a “small number” of his civil servants stayed at the 19,000-acre ranch of Philip Anschutz in July last year as part of a nine-day, four-state US trip, The Times has learnt.

Last night a spokesman for the department said that the visit happened “on a day off”. He added that the two men did not discuss business, Mr Prescott’s Permanent Secretary was informed in advance and Mr Prescott subsequently made a donation for the value of a hotel room to a July 7 charity.

However, Opposition MPs said that the incident once again raised questions over Mr Prescott’s judgment. On Monday Hugo Swire, the Tory Shadow Culture Secretary, will write to Mr Prescott demanding to know about the links between Mr Anschutz, his companies and government ministers.

The stay has not been declared in the Register of Members’ interests and could conflict with section 5.24 of the ministerial code, which insists that “no Minister or public servant should accept gifts, hospitality or services from anyone which would, or might appear to, place him or her under an obligation”.

The ministerial code says that members of the Government would normally be required to register hospitality valued at more than £550. A spokesman said that he was unable to say the exact value of the donation that was paid, when it was made or precisely how many civil servants accompanied Mr Prescott.

The US visit took place between July 17 and 26, 2005, with Mr Prescott visiting Washington, Texas, Colorado, Denver, and Los Angeles. The penultimate leg of the trip, to the owner of AEG entertainment, which owns the Dome, will raise most questions.

Mr Prescott has publicly defended the government deal to sell the Dome to AEG. Last year he insisted that the sell-off represented “fantastic value for money, both for the taxpayer and local residents alike”.

In June 2004 English Partnerships concluded the deal with Meridian Delta Ltd and the Anschutz Entertainment Group for the redevelopment over 20 years of the whole of the northern Greenwich Peninsula, including the Dome. The deal was overseen by English Partnership’s sponsoring department, the Office of the Deputy Prime Minister. However, a spokesman insisted that Mr Prescott played no personal role in the negotiations or the drawing up of contracts.

The Dome was handed over to the consortium free, although taxpayers will receive returns expected to be £216 million over the course of the contract. This is dwarfed by the £800 million spent by taxpayers on building the Dome.

AEG wants to reopen the Dome next July as a £600 million arts centre, with a 23,000-seater stadium, an 11-screen cinema, a nightclub, bars and restaurants, an ice rink and a 350-room hotel.

In 2002 the Meridian Delta Consortium, AEG’s partners in the Dome deal, said that its Dome profit-sharing agreement with the Government would kick in only once a minimum profit threshold was reached. Up to the threshold, which was not revealed, all profits would go to the developers.

A spokesman for Mr Prescott said: “The Deputy Prime Minister visited the United States in July last year for a series of meetings with government officials and to give some speeches. The purpose was to promote political and business interests. The Permanent Secretary was informed of every element of the visit.

“It was a nine-day visit which straddled a weekend. He stayed at Phil Anschutz’s home near Denver for part of the weekend. The party would have stayed in the hotel at any rate so a donation was made to cover the equivalent cost.”

The spokesman said there was no conflict of interest, despite his department’s involvement in the sale of the Dome. “Mr Prescott had no role in planning decisions or contractual negotiations in relation to the sale of the Dome. Planning applications concerning the Dome were dealt with by other ministers and this is standard practice. Parliament was informed of that procedure.”

A spokesman for Mr Anschutz refused to comment.

Mr Swire said: “I think that this is very compromising for John Prescott. I shall be writing to him on Monday to clarify the nature of his relationship with Anschutz. I shall now also be asking a question of every minister what meetings they have had in the last two years with any potential bidders.”

Don Foster, Lib Dem culture spokesman, said: “It shows his judgment must be questioned. He must make absolutely clear the circumstances of this visit, his connection to Mr Anschutz and what money changed hands, otherwise people will draw the wrong conclusion.”

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• Looking for romance on the Blairs' love bus
• Children 'immersed in culture of violence'
• Hunt for black gold sweeps the country