A retired teacher from Norfolk has become the sixth from a leading private school to be convicted for historic sexual abuse charges.

Roger Martin, 83, of Great Dunham, King's Lynn, has been jailed at Hove Crown Court for four years for the indecent assault of a 10-year-old pupil at Christ's Hospital School, Horsham, West Sussex, between September and December 1976.

As well as the prison sentence, he will be a registered sex offender indefinitely.

Detective Sergeant Rebecca Wilde, of Sussex Police, said: "It became clear that Martin, who was the boy's housemaster, took advantage of his natural vulnerability for his own sexual gratification, hoping that it would not come to light, for more than 40 years he was right.

"This victim had kept the experience to himself for more than 40 years, only coming forward when he learned of similar cases involving other teachers at the same school.

"We have had full co-operation from the school throughout the investigation and we make it clear that the case relates to a period nearly 43 years ago, having nothing to do with current or recent pupils or staff at the school."

Simon Reid, current headteacher at Christ's Hospital School, said: "Both this and the convictions of other former teachers have exposed a dark period in the school's history during which too many children were manipulated and exploited.

"These individuals abused their positions of trust in a most serious and abhorrent way; the survivors of their offences have shown extraordinary courage in bringing them to justice.

"It is difficult to imagine the impact that these awful experiences must have had on their lives."

An NSPCC spokesman said: "Martin exploited his position of trust and authority to subject a young boy to appalling abuse. He may have believed he had got away with this sickening crime but this case shows that survivors of child sexual abuse will be listened to, no matter how many years have passed or who the abuser was.

"This is the latest conviction involving child abuse at Christ's Hospital School, and it is crucial that all those affected are receiving the support they need to help them recover."

Last month, chaplain Gary Dobbie was jailed for 12 years for abusing nine pupils across three decades.

Sports coach Ajaz Karim, was jailed last August for 10 years after assaulting six girls between 1985 and 1993.

And a month previously, James Husband, also known by his middle name of Andrew, was jailed for 17 years for raping and indecently assaulting a girl as young as 14 between 1990 and 1994.

Peter Webb and Peter Burr admitted indecently assaulting pupils at the school between the 1960s and 1980s and were also jailed.

Christ's Hospital is one of the oldest boarding schools in the country, dating back to the 16th century, and the Queen is a patron.

Pupils still wear a Tudor-style uniform of a long blue coat and high yellow socks with boarders charged fees of up to £31,500 a year.

Poet Samuel Taylor Coleridge and Sir Barnes Wallis, inventor of the bouncing bomb, are counted among its famous alumni.