The source said: “At that time, the Duke went to tramp a lot. He was at a birthday party the same week for one of the Sangsters.”
The source questioned how the new eyewitnesses – 18 years on – could be sure they had seen the Duke dancing with Ms Roberts.
While the Duke would be memorable, it would be unlikely for them to be sure the woman he was with was Ms Roberts, rather than a female friend.
The Duke, now aged 59, has insisted he was at Pizza Express in Woking on same the evening he is accused of visiting Tramp with Ms Roberts, who is now 35, and later having sex with her.
He has insisted she is mistaken because he did not sweat at the time – as she alleged – and did not wear ‘travelling clothes’ in London but rather a suit and tie on all occasions.
Lisa Bloom, a Los Angeles-based lawyer representing five victims of Epstein, a multi- millionaire financier, said two people had now contacted her – in the wake of the Duke’s disastrous interview with the BBC’s Newsnight – to insists they had seen him with Ms Roberts.
Ms Bloom told the Mail on Sunday: “The first woman, a Londoner, contacted me after she saw Prince Andrew’s interview.”
Ms Bloom said the woman was with a companion who corroborated her version of events.
Ms Bloom added: “The FBI is looking in to Prince Andrew. They want to speak to him.
“The woman was in Tramp with a friend who said: ‘Look, there’s Prince Andrew… he was with a young woman she now knows was Virginia Roberts.
She remembers that Prince Andrew was smiling and seemed to be happy and Virginia was not. Virginia not smiling made an impression too.”
The difficulties for the Duke were compounded by the emergence of a photograph yesterday showing Epstein at Windsor castle, flanked by Ms Maxwell and Harvey Weinstein, the former film tycoon charged with rape and other sexual offences which he denies.
Epstein, who was 66 when he committed suicide, was invited to Windsor by the Duke to celebrate the 18th birthday of his daughter Princess Beatrice.
When the party took place in July 2006, police in Florida had already prepared an arrest warrant for Epstein on child sex abuse charges.
Ms Maxwell is also under investigation for allegedly procuring girls for Epstein including Ms Roberts. Ms Maxwell denies all wrongdoing.
Buckingham Palace declined to comment yesterday.