Tony Blair insisted last night that there was no evidence that John Prescott had inter-fered in the selection process for Britain's only super-casino.

The Prime Minister said he did not understand the row over Mr Prescott's relations with the US billionaire owner of the Millennium Dome who is bidding for the casino licence.

Indicating that he would stand by the Deputy Prime Minister, who would stand in for him "as normal" when he goes on holiday next month, Mr Blair said: "Let me just check my facts on this, but my understanding is that the planning is done by the local council and the Mayor, so . . . has anybody got any actual evidence that John has inter-fered in this process in an improper way?

"I haven't seen any. I mean I've seen hoards of newspaper allegations about something to do with cowboy boots and some belt or something."

Mr Blair conceded there was an issue about whether the Deputy Prime Minister should have detailed his stay at Philip Anschutz's Colorado ranch last year in the register of MPs' interests.

But he said the visit had now been entered.

He added: "This is a group that . . . has put together £5 billion investment around the Dome. It will create somewhere in the region of 20,000 jobs and more than 10,000 houses in London. That whole area of London is going to be regenerated. Why, why should we not want him to come and do this?"

Earlier it was revealed that Mr Prescott had discussed plans to open a super-casino at the site during controversial trips to the US.

Tim Lieweke, chief executive of Anschutz Entertainment Group, told an American newspaper that the issue came up "in a couple of conversations that were very minimal and insignificant".

The Tories claimed the account was "at odds" with the Deputy Prime Minister's claims about his stay at the ranch of Philip Anschutz, the billionaire owner of AEG.

But a spokeswoman for Mr Prescott said that Mr Lieweke's comments proved that there were no discussions about casinos.