Senior Whitehall mandarins repeatedly warned former Prime Minister Margaret Thatcher against knighting Jimmy Savile because of long-standing concerns over his private life.

Previously unseen Cabinet Office papers reveal that suspicions about the DJ’s “strange and complex” personality were known at the highest level for decades.

Lady Thatcher – who invited the presenter to Chequers – made four attempts to appoint Savile to the knighthood before eventually succeeding in the final year of office in 1990.

Download the new Independent Premium app Sharing the full story, not just the headlines

The veteran charity campaigner was revealed as one of Britain’s most prolific sex offenders following his death in 2011 having used his celebrity status to abuse hundreds of victims some as young as eight years old.

Papers seen by The Sun reveal that Labour Prime Minister Harold Wilson rejected calls to award him an MBE in 1970 although he was appointed OBE the following year.

Mrs Thatcher first sought the honour for Savile in 1986.

But a letter from Private Secretary Nigel Wicks to then Cabinet Secretary Robert now Lord Armstrong said: “She wonders how many more times his name is to be pushed aside, especially in view of all the great work he has done for Stoke Mandeville.

“She would therefore like you to consider further the inclusion of his name in this list.”

A letter from Lord Armstrong warned that the case of the Jim’ll Fix It presenter was “difficult”.

It adds: “Mr Savile is a strange and complex man. He deserves high praise for the lead he offers in giving quiet background help to the sick. But he has made no attempt to deny the accounts in the press about his private life two or three years ago.”

Reports of the time featured boasts from Savile that he had slept with numerous women whilst taking part in charity events – a claim that was at odds with the Government’s battle against the spread of HIV and Aids.

Savile raised more than £30 million for good causes, including £12 million to rebuild the National Spinal Injuries Centre at Stoke Mandeville Hospital in Aylesbury, Buckinghamshire. Since his death more than 200 offences have been recorded against him mostly against children.

In the same year that he was awarded his British knighthood Pope John Paul II made him Knight Commander of the Pontifical Equestrian Order of Saint Gregory the Great – the Roman Catholic Church’s highest honour.