A new documentary about the attempted kidnapping of a member of the royal family will feature an interview with the Norfolk man who helped save her life.

On March 20, 1974, Ron Russell tackled a crazed gunman who shot four people as he tried to drag Princess Anne out of a royal car at the Mall in London.

'Princess Anne: The Plot to Kidnap a Royal' is available to watch on Channel 4 tonight (Sunday, June 25) and tells the story of the princess's narrow escape that day.

Mr Russell, a 6ft 4in former boxer, landed a punch on the attacker Ian Ball, enabling police to overpower the assailant who had planned to ask the Queen for a £3m ransom in used fivers.

Eastern Daily Press: Ron Russell, the former boxer who helped save Princess Anne's life in 1974. Ron Russell, the former boxer who helped save Princess Anne's life in 1974. (Image: Archant)

It was an act of bravery that earned Mr Russell the top peacetime gallantry award, the George Medal, and a moment of fame which has followed him ever since as he ran pubs and a roofing business in Norfolk.

Speaking to this newspaper in 2006, Mr Russell said: “I pulled over and heard a lot of banging and smashing which I thought was the general rumpus. But then Ball shot a policeman, and I thought 'that's a liberty, he needs sorting'.”

READ MORE: Tragedy of Princess Diana pallbearer who died on Norfolk streets

Eastern Daily Press: Ron Russell, who lives in Norfolk, pictured in 2006. Ron Russell, who lives in Norfolk, pictured in 2006. (Image: Archant)

READ MORE: New film on life of Norfolk's princess turned suffragette

The former heavyweight boxer went to punch Ball but only hit the back of his head.

“He turned round and fired at me. It missed by millimetres and hit a taxi windscreen.”

After trying to help the shot policeman he returned to the car, where Ball was trying to drag Anne from the car.

Mr Russell pulled her out and then hit Ball "fair and square" on the chin.

"He went down and police were everywhere," Mr Russell recalled.

The documentary is on Sunday, June 25 at 8pm or stream on Channel4.com.