Victor Montagu, a former Conservative MP, was let off with a caution in 1972 for indecently assaulting a boy for nearly two years, files released by the National Archives reveal

A top Tory politician escaped prosecution for child abuse in the 1970s after promising not see his victim again.

Victor Montagu, a former Conservative MP, was let off with a caution in 1972 for indecently assaulting a boy for nearly two years, files released by the National Archives reveal.

The decision meant Montagu never stood trial and his widespread paedophile abuse were never exposed.

According to files published by the Guardian today, the then chief public prosecutor Sir Norman Skelhorn dismissed the abuse as 'not of themselves very serious'.

He said: 'If Mr Montagu is prepared to… avoid any contact with the boy in the future I do not think that proceedings are called for.'

Sir Norman is the same prosecutor who refused to charge the Liberal MP and serial abuser Cyril Smith in 1970.

Montagu, who died in 1995, was the MP for South Dorset from 1941 to 1962 and became the 10th Earl of Sandwich in 1964.

The files revealing that a prosecution against him for indecently assaulting a young boy was not pursued have been kept secret for more than 40 years.

They were released earlier this week after an application under the Freedom of Information Act by the Guardian newspaper.

The files show a boy was interviewed on 10 November 1972 after rumours that he was being sexually abused.

Two officers visited Montagu at his home in Mapperton, Dorset, and interviewed him under caution.

Montagu's youngest son, Robert (pictured), last year revealed that his father had abused him on an almost daily basis for four years from when he was just seven years old

He was later charged by police with two counts of indecently assaulting a male under 16 on a number of occasions between 31 December 1970 and January 1972 and of indecently assaulting the same boy between 31 December 1971 and November 1972.

But when the then chief constable of Dorset and Bournemouth, Arthur Hambleton, wrote to Skelhorn for advice on the case, prosecutors chose to give Montagu a caution instead of proceeding with a criminal trial in public.

The revelation comes after Montagu's youngest son, Robert, last year revealed that his father had abused him on an almost daily basis for four years from when he was just seven years old.

Speaking to the Guardian tonight he revealed he had no idea a prosecution against his father had been dropped.

He said he knows 10 people who were abused by his father as children but he believed there may be up to 20.

'It doesn't surprise me altogether but I didn't realise that it went on so late into his life,' he said.

'I had no idea he was ever visited by the police at home or charged. My father was a loner, I don't think he was part of any Westminster paedophile ring, but he was right there at the time.