A failed assassination attempt on the Queen during a royal tour of New Zealand in 1981 was covered up to “avoid jeopardising” future royal visits, a former police officer has claimed.

Nearly four decades on from the incident, Tom Lewis, an ex-Dunedin detective sergeant, has alleged that a troubled teenager shot at the Queen and came yards from hitting her.

In an interview with the New Zealand website, Stuff, Mr Lewis claimed that Christopher John Lewis, then 17, fired at the Queen as she alighted her motorcade to greet a crowd gathered at the Otago Museum Reserve.

However, Mr Lewis claims that the attempt on the Queen’s life was quickly covered up by police and the New Zealand Government, which feared that the near-miss would scupper any chance of her returning to the country.

He added that, as the distinctive crack rang out around the area, police attempted to disguise the seriousness of the threat, telling British journalists present that the noise was a council sign falling over.