Princess Diana's brother Charles Spencer has alleged they were both physically abused by one of their nannies

He continued in a candid interview for BBC One's 'Sunday with Laura Kuenssberg', which airs this weekend: "It wasn't a tap on the wrist, it was a cracking crunch, you know, and I remember it still."

Charles insists he does not put the blame on his parents, the late John Spencer and Frances Spencer.

The journalist has opened up on his mistreatment and being sexually abused as youngster in the memoir 'A Very Private School'.

He claims a female member of staff at Maidwell boarding school groomed him and other boys and that headmaster, John Porch, gave them "brutal beatings".

In response to the serious claims, the school said in a statement: "It is sobering to read about the experiences Charles Spencer and some of his fellow alumni had at the school, and we are sorry that was their experience.

"It is difficult to read about practices which were, sadly, sometimes believed to be normal and acceptable at that time. Within education today, almost every facet of school life has evolved significantly since the 1970s. At the heart of the changes is the safeguarding of children, and promotion of their welfare."

Also in the tome, Charles claimed he lost his virginity to a prostitute on a family vacation when he was just 12 years old.

He used his pocket money to pay the woman £15 for his first time having sex, and admitted the experience left him feeling "hollow and cold".

The aristocrat said his preteen years were characterised by "casual cruelty, sexual assault and other perversions".

After attending boarding school for most of his young life, Spencer headed to Eton College and later attended Magdalen College in Oxford to study history.

He then worked as a journalist and broadcaster for NBC News and Britain's ITV Granada.

Charles became an earl and inherited his family's estate, Althorp, in 1992 after his dad died.

Diana died aged 36 in a 1997 Paris car smash and her brother has always been outspoken about the way she was treated by the media, insisting in the interview with Kuenssberg that it was "more dangerous" than the conspiracy theories surrounding Catherine, Princess of Wales, 42, who apologised for Photoshopping a family photograph, the first to be released amid her recovery from abdominal surgery.