UK This is London] – An American porn star has been flown to Britain by detectives investigating the cash-for-honours investigation, it was revealed today.

Californian actress Courtney Coventry, 25, was questioned by police yesterday over her links with Labour’s chief fundraiser Lord Levy. Mrs Coventry was introduced to Tony Blair by Lord Levy at a fund-raising ball at the Hilton Hotel in 2004.

She and her British-born husband John Coventry were invited to the event after claiming to be a real life Count and Countess.

Mrs Coventry – wearing a giraffe-print dress and bright red lipstick – was introduced to the Prime Minister as the Countess of Rozel, a title the couple had bought for a few hundred pounds.

The actress was flown to Heathrow from Nice yesterday after she contacted detectives to say she had crucial information on the cashforhonours affair.

A Yard source said today she had been questioned about what she knew but detectives had quickly dismissed her information as valueless. The source said: “We spoke to her in person but we decided she did not have anything of interest to say so she was not formally interviewed. In effect, she was time wasting.”

Earlier this year the actress – whose soft-porn credits include the film Dirt Merchant – told how easily she and her husband had duped Labour fund-raising officials after they had paid £1,000 to attend the Labour fundraising ball at the Park Lane Hilton.

She said: “The fake aristocratic title should have shown up in the vetting procedure. But it was clear Lord Levy and the Labour Party were interested only in how much money I could give them.”

Mrs Coventry told how she had a conversation with the Prime Minister in which he talked about his vision for the future and how she chatted to Jack Straw. She said: “He spent most of the time talking to my chest.”

Meanwhile, it emerged that police investigating the cash-for-honours affair were told that Tony Blair would quit earlier if he had been quizzed as a suspect.

The Metropolitan Police team of detectives received the stark warning from Number 10 in January as they were preparing to grill the Prime Minister under caution.

In the end, Mr Blair was questioned by police only as a witness. But these claims are sure to be seized on by critics as proof that No 10 pressured the investigating officers by raising the prospect of a constitutional crisis.