The Hollywood star has hinted previously she was a victim of the disgraced movie mogul. Sources said British police are looking at two other allegations.
More than 60 women, including Cara Delevingne and Gwyneth Paltrow, have accused the 65-year-old of sexual misconduct.
The 47-year-old mother-of-three said during the alleged attack at The Savoy: “It was such a bat to the head. He pushed me down. He tried to shove himself on me. He tried to expose himself.
"He did all kinds of unpleasant things. But he didn’t actually put his back into it and force me.”\
A friend of the actress, make-up artist Ilona Herman, claims she told her at the time Weinstein had threatened to derail her career.
Ms Thurman added: “The complicated feeling I have about Harvey is how bad I feel about all the women that were attacked after I was. I am one of the reasons a young girl would walk into his room alone, the way I did.”
The Savoy attack, she claimed, followed an incident in Paris where she says Weinstein tried to lure her into a steam room.
Afterwards Ms Thurman says she was wary of Weinstein, but continued to work on his movies, including the cult Kill Bill series.
A spokesman for the disgraced former Miramax boss said: “Mr Weinstein acknowledges making an awkward pass 25 years ago at Ms Thurman in England after misreading her signals, after a flirtatious exchange in Paris, for which he immediately apologised and deeply regrets.
“However, her claims about being physically assaulted are untrue."