The 62-year-old broadcaster attended Edinburgh Academy, a fee-paying school, between 1966 and 1978, from aged five to 17.

Warning: This story contains descriptions which some readers may find distressing

He told the Scottish Child Abuse Inquiry (SCAI) that he was sexually assaulted by a teacher, Hamish Dawson, who died in 2009, and alleged he witnessed a primary-age child being sexually assaulted by another teacher, Iain Wares, whom he compared to Savile.

Savile, who is believed to be one of Britain's most prolific sex offenders, died in 2011 aged 84, having never been brought to justice for his crimes.

Permission was given by the inquiry's chair earlier this year to identify Wares, 83, who was previously a "protected person" and was referred to by a pseudonym.

Campbell first detailed his claims of sexual abuse last year, on an episode of his podcast Different on BBC Sounds.

Speaking on Tuesday, Campbell said he was still "haunted" by his schooldays and had previously turned to prescription medication to cope with the bad memories, but described his decision to share his experiences at the inquiry as "the best decision he had ever made".

Campbell said he had largely hidden the abuse from his adoptive parents, Sheila and Frank Campbell, saying it began in junior school but escalated in senior school.

He described a moment in preparatory school when he allegedly saw Wares molesting a young pupil in the showers.

'The smell of carbolic soap is triggering'

Campbell said: "This has haunted me since it happened.

"It all haunts you. I have had my penis touched by a teacher.

"The smell of carbolic soap is triggering.

"I remember Wares leaning over the back of my friend and masturbating him."

Campbell also said when he was 14 or 15 years old, he was attacked by a teacher so violently that a friend who witnessed it thought he was being mugged by a stranger. The teacher cannot be identified for legal reasons.

He said that after the alleged assault, when he threatened to contact the police, his mother had contacted Edinburgh Academy.

He described himself as a "survivor" and said: "I'm 62 years old but Hamish Dawson's hands are still in my underwear playing with my penis."

He also described the physical assault by another teacher as "being tossed like a ragdoll, punching and kicking me," and said the abuse "helped shape our lives in the most heinous way".

Wares has reportedly been fighting extradition to face charges following allegations against him during his time as a teacher in the 60s and 70s. The BBC report Wares has denied the allegations against him.

The BBC presenter became visibly angry when speaking about Wares living in a "plush retirement home" - and demanded a public apology from Edinburgh Academy, claiming it moved the teacher on to Fettes College, another high-profile school also in Edinburgh.

Campbell said: "You sent him there after a parent complained. You must [apologise] unreservedly and do it now."

He said mandatory reporting (the legal requirement for those who work with children or in law enforcement to report child sexual abuse) "breaks this pernicious code," and urged for it to be brought in.

A spokesman for the Crown Office and Procurator Fiscal Service (COPFS) said: "This has been a complex investigation and COPFS appreciates that it has been difficult for all those involved.

"In order to protect any future proceedings and to preserve the rights of the complainers, the Crown will not comment further at this stage."

Campbell wrote a memoir, Blue-Eyed Son: The Story Of An Adoption, published in 2004, and was given an OBE for services to children in the Queen's birthday honours in 2015.

An Edinburgh Academy spokesperson said: "Schools should be safe places for everyone and, at various points in our history, this was not the case for too many of our pupils.

"They were wronged by specific individuals whose roles were to educate, protect and nurture them. For this, the Edinburgh Academy unreservedly apologises.

"We recognise that abuse during childhood has wide-ranging consequences for that individual throughout their life and we are fully committed to supporting our former pupils and helping in the investigations into accusations of historical abuse.

"Given the seriousness of these matters, we believe it's right that we give our views to the inquiry in the first instance and reserve any detailed comment for an appropriate time when its work has progressed.

"The Edinburgh Academy thanks those members of our community who have come forward and assisted the SCAI with its proceedings. This will have been an incredibly difficult undertaking and we applaud their courage in doing so."