A former school chaplain has been jailed for three-and-a-half years for a string of sex offences on pupils spanning three decades.
Leslie Carter, 84, from Bathwick Street in Bath, admitted 18 counts of indecent assault on six schoolboys between 1956 and 1978.
Scotland Yard said the "unrepentant paedophile" committed his attacks in the UK and South Africa, as well as on board a ship between the two countries.
Officers said there were "undoubtedly other victims", and urged people to come forward as the elderly man was jailed at Harrow Crown Court. His victims were aged between seven and 14.
Police said one man contacted them in 2004 to report that he had been abused by Carter while he was a pupil at St George's Grammar School in Cape Town, South Africa.
The paedophile persuaded the victim's family to allow him to travel to London and sexually abused the schoolboy during the boat trip to London and when they stayed at his family's house in Sylvan Road, South Norwood, police said.
In March last year, a second victim contacted Quintain Hall School in Harrow to report that he had been sexually abused by Carter while he was a pupil at the school in the Seventies when Carter was a chaplain.
Carter pleaded guilty to nine counts on September 13 and a further nine at the latest hearing.
Detective Constable Rachel Snow, from the Metropolitan Police child abuse investigation team, said: "Carter is an unrepentant paedophile who preyed on any vulnerable child that came in contact with him. He had a particular preference for young boys. There are undoubtedly other victims of Carter's who have not yet come forward.
"I would urge anyone who has been sexually abused by Carter, or anyone else, to make contact with the police. They will be treated with respect and their allegations will be taken seriously."