The Queen was nearly assassinated by a teenager when she visited Dunedin in 1981, a retired police officer has claimed. The assassination attempt was later covered up by New Zealand authorities over fears the monarch would refuse to visit the country in the future.

Former police detective Tom Lewis said the assassination attempt occurred when 17-year-old Christopher John Lewis shot at the royal motorcade in October 1981. Lewis told the Stuff website that the teen narrowly missed the Queen.

Lewis said police and government officials covered up the would-be assassin's actions. Many who were present at the royal event heard the gunshots, but authorities claimed at the time it was merely the sound of a council sign falling over.

"You will never get a true file on that, it was reactivated, regurgitated, bits pulled off it, other false bits put on it," Lewis said. "They were in damage control so many times."

According to The Independent, Christopher Lewis told investigators he had been ordered to assassinate the Queen by a mysterious Englishman by the name of "Snowman". Christopher told police that pro-Nazi, far-right groups were "sprouting up" across New Zealand and that he wanted to lead a local terror cell.

After being investigated for a non-related burglary incident, Christopher Lewis led investigators to a fifth story toilet in a building overlooking the Queen's route. Police found a .22 calibre rifle and empty shell casings.

Despite the assassination attempt, the teenager was only charged with possessing a firearm in a public place and discharging a weapon. Christopher Lewis was later jailed for three years and taken to a psychiatric hospital in 1983, where he concocted a new assassination plot to kill Prince Charles during another royal visit to New Zealand.

He spent much of his adult years in and out of prison and was charged in 1996 with the murder of mother-of-three Tania Furlan. DNA evidence would later clear Christopher Lewis of that crime. He committed suicide in 1997 at the age of 33, while he served jail at Mount Eden prison in Auckland.