Sir Edward Heath, the former prime minister, has been accused of raping a 12-year-old boy more than 50 years ago.
The alleged victim, who is now 64, has claimed that Heath attacked him at a flat in Mayfair in 1961, the Daily Mirror reported.
Scotland Yard refused to comment on whether officers had been informed of the allegations when asked by ITV News.
The claims come after the police watchdog announced it was to investigate an alleged cover-up of child sex allegations against the ex-prime minister, who died in 2005.
The man - who claimed to have been abused throughout his childhood by his father and his friends - said Sir Edward picked him up along the A2 road in north Kent after he had run away from home.
He claimed he was then raped in a property in Park Lane.
Five years after the alleged sexual assault, the man said he recognised Heath when he saw a picture in a newspaper of the then MP for Bexley standing beside Margaret Thatcher.
He said he broke down in tears and told his mother: “The man in this picture raped me, mum”.
In statements to his legal team reported in the Mirror: “I learned that he was MP for Bexley.
"This answered a lot of questions as to why no-one believed me about the London saga. I got called a liar and a fantasist.”
Sir Edward, who was prime minister between 1970 and 1974, is the highest-profile figure to be embroiled in historic abuse allegations against prominent figures.
The Independent Police Complaints Commission (IPCC) is looking into whether Wiltshire Police followed up a claim against Sir Edward, which was made in the 1990s.
Wiltshire Police have also appealed for potential victims of Sir Edward to come forward, after launching an inquiry on the back of allegations made by a retired senior officer.
Sir Edward died in Salisbury, Wiltshire in 2005.