John Prescott is to face a full investigation by the Parliamentary Commissioner for Standards into his mini-break on the ranch of the billionaire owner of the Millennium Dome.

Sir Philip Mawer has announced that he hopes to complete the investigation before the summer recess, when Mr Prescott is due to take over the running of the country from Tony Blair.

The inquiry is a particular embarrassment for the Deputy Prime Minister because he met with the commissioner yesterday in an attempt to stop a full probe taking place.

Mr Prescott took to the airwaves this morning to insist he would remain in office despite the barrage of criticism over his two-day stay at the 32,000-acre American ranch of Philip Anschutz last July.

"I will get on with doing my job and I am not leaving it, I am getting on with it," he said, adding it would be wrong to bow to pressure from the Tories and the media.

But in the same interview he admitted he did have a formal role with the Dome — and that the reason Mr Anschutz met him seven times was to give him "regular updates on the project".

This would appear to undermine Mr Prescott’s spokesman who has insisted that he only ever talked about post-sale and regeneration issues.

The Deputy Prime Minister said that the meetings took place approximately once every six months, but he would have met him every three months if necessary.

In the combative interview with BBC Radio 4's Today programme, the Deputy Prime Minister also refused eight times to deny rumours that have been circulating the internet that he had a second affair, insisting he had said all he wanted to on the matter.

"I am very sorry for what has happened. I do believe in a way it’s not been good for my party or Government. Of course I am conscious of that.

"All my life has been that, I have never had another job, I had never had a penny off anyone else, all I’ve done is this job, but when I get involved, as I have been, in these incidents I am extremely sorry."

He said that after Mr Anschutz had acquired the Dome lease, he had agreed to meet every six months so that he could be updated on progress at the site. He praised the tycoon for taking on the Dome and turning a "poisonous bit of land" into a "jewel of London".

"If a man asks to see me, if he comes offering that, I will see him every three months," he said.

He stressed that he had not discussed the Dome when he and three officials stayed at Mr Anschutz’s ranch last year as the issue had been dealt with at their earlier meetings.

He said he had accepted the invitation, during a working visit to the US to discuss agriculture and international trade, in order to see a working ranch for himself.

"That is why I took that opportunity, probably not only to look at a working cattle ranch but to visit one. I am curious about it. I saw the cowboy films over my young years, I was interested to have a look at it," he said.

Previously his office had said the main subject of discussion was the abolition of the slave trade.

He said that he could not be responsible if civil servants "down the line" were affected by his personal relationship with Mr Anschutz.

"If you say to me, were there some civil servants down the line exercising some judgment about this in a view of the circumstances, I was not involved in it, didn’t even know about it until I read in the press, totally reject any idea I expressed any pressure whatsoever.

"The suggestion at the end of the day was my meeting with Mr Anschutz was somehow giving him preference for a bid. It was not, I did not get involved and there is no evidence to that fact at all."

Asked whether his departure would prompt an election for the deputy leadership of the Labour Party , Mr Prescott said that there was "no need" for one under the party’s constitution.

Many commentators have argued that the principal reason Mr Prescott is still in office is the avoidance of such a potentially damaging vote.

The interview came as documents obtained under the Freedom of Information act showed that officials in Mr Prescott's department demonstrated a keen interest in a Dome casino in the same period the Deputy Prime Minister was having repeated meetings with Mr Anschutz.

"I have no doubt that my officials might have been talking about that," said Mr Prescott today.

In a briefing on August 8, civil servants in Mr Prescott's department suggested that the culture minister Lord McIntosh should meet with senior executives of AEG to discuss the project. Then, in minutes for a meeting in September 2003, a Prescott official "specifically asked" to be kept informed by the Culture department about any further meetings regarding the Dome casino.

Mr Prescott revealed yesterday that he had seven meetings with Mr Anschutz between August 2002 and July last year, including one on June 18 2003 in London -- shortly before these two episodes.

Last night Mr Prescott admitted to the BBC that Mr Anschutz raised the subject of opening a casino in the Dome, but the Deputy Prime Minister replied that this was not within his jurisdiction.

On Tuesday, a letter to the Conservatives stated "no discussion took place about the sale of the Dome, nor about the awarding of regional casino licences." A spokeswoman for Mr Prescott said this exchange did not amount to "a discussion".

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads