More bad press for the diamond jubilee riverboat pageant after it was revealed that one of the guests on board the Royal Barge is a convicted sex offender.

Harbinder Singh Rana, invited as a guest of Prince Charles, has served time in prison for a series of attacks on women. During his time on the barge, Rana came into close proximity with the Queen, Prince Philip, Prince Charles, Camilla, the Duke and Duchess of Cambridge and Prince Harry.

During his trial in 1986, a jury heard how he tricked his way into his victims’ homes by posing as a doctor before subjecting them to internal examinations. He was sentenced to four years after being convicted of five counts of indecent assault, 11 counts of assault causing actual bodily harm and one of attempted assault.

Confronted by the Daily Mirror yesterday, Rana, who has met Charles several times through a British Sikh charity he is involved with, said, "The fact that the Prince of Wales invited me clearly shows what I have done for the community since then.”

A spokesman for Clarence House said: “The office of Prince Charles was unaware of his previous convictions.”