Worldwide fame is part and parcel of life as a British Monarch, and even more so for Queen Elizabeth II than her predecessors; her renown is amplified by having ascended to the throne during the era of modern communications, and since becoming Britain’s longest-reigning sovereign.

That reign was very nearly cut short in 1981 – 34 years before The Queen would surpass the rule of her great-great-grandmother Victoria – when a young, disturbed man fired a weapon at her as she rode in Trooping the Colour.

Marcus Serjeant wanted to kill The Queen. He wanted to kill The Queen, he said, because “I wanted to be famous. I wanted to be somebody.” He had seen Mark David Chapman leech some of John Lennon’s fame by murdering him in 1980. He had seen the whirls of publicity that surrounded attempts to assassinate Ronald Reagan and Pope John III.

Writing in his diary, Sarjeant claimed that “I am going to stun and mystify the world. I will become the most famous teenager in the world.” The outpouring of public grief in response to Lennon’s death led Serjeant to tell a friend: “I would like to be the first one to take a pot shot at The Queen.”

Fortunately, Serjeant failed in this twisted, short-sighted ambition, just as he had with most other undertakings in his adolescent life. By the age of 14, he seemed set on a career in the military; he joined the Air Training Corps in 1978, and won a badge for marksmanship. He finished school in 1980 and attempted to join the Royal Marines, but left three months later when he was unable to meet the disciplinary standards. A subsequent, half-hearted attempt to enlist in the Army came to nothing when he quit two days into the induction course.

By the end of the year, his outlook had darkened. Serjeant’s desire to be part of the establishment seemed to morph into something quite the opposite. He joined the Anti-Royalist Movement in October. He tried to buy ammunition for his dad’s .455 Webley Revolver, and, unable to do so, obtained a gun licence in order to buy two blank-firing revolvers of his own. In a letter to Buckingham Palace, Serjeant wrote: “Your Majesty. Don’t go to the Trooping the Colour ceremony because there is an assassin set up to kill you, waiting just outside the palace.”

On the day of the Trooping of the Colour, Marcus Serjeant went to the junction of The Mall and Horse Guards, became part of the crowd, and waited. His letter arrived at the palace four days after the ceremony.