On a bright and sunny day in June 1981, a teenager left his home near Folkestone and travelled into London with the intention of writing his name into history in the darkest way possible. He was going to shoot the Queen.

Marcus Sarjeant was just 17 when he arrived in the capital for the annual Trooping of the Colour - a traditional military parade through the very heart of the city full of pomp and ceremony.

Tourists and well-wishers alike would gather to cheer on the Queen and other members of the royal family, lining the route as they travelled from Buckingham Palace to Horse Guards Parade, just off Whitehall.

Tradition would see the Queen ride through the streets.

The royals were enjoying revived popularity. After the Queen's 1977 jubilee celebrations, the emergence of Princess Diana had injected fresh enthusiasm, especially with her marriage to Prince Charles taking place later that year.

But the 1981 parade would be unlike any other.

On the morning of the event, Sarjeant had penned and mailed a chilling note to Her Majesty.

It read: "Don't go to the Trooping of the Colour today because there is an assassin waiting outside to kill you."

The would-be assassin was the youngster - and what he would do that day would see him become the last person to be charged under the Treason Act of 1842.

He was an unlikely gunman.

Living in Capel-le-Ferne, near Folkestone, he came from a "good family" who were described as "well off".

He had attended Astor Secondary School, now Astor College, in neighbouring Dover.

He was an active youngster, joining the Scouts and becoming the local patrol leader.

His hobbies included collecting stamps and butterflies and it was said he had a poster of Charles and Diana on his bedroom wall.

Friends described him as friendly but something of a loner.

In 1978 he left to join the Air Training Corps where he again excelled, with his talent with his air rifle winning him a marksman's badge.

Two years later he had left school with seven CSEs under his belt and continued his military career dreams by joining the Royal Marines.

But after just three months he left - claiming he had been bullied.

Efforts to join the Army were even more short-lived as he quit after just a matter of days.

Hopes of joining the police or fire brigade also came to nothing - leaving the hopes of the youngster to serve his country in a worthy profession in tatters.

The dawn of the 1980s had come with a string of high-profile assassination attempts.

In December 1980, Beatles star John Lennon had been killed by an obsessed fan outside his apartment in New York, prompting an outpouring of public grief.

In March 1981, US president Ronald Reagan was shot by a fan obsessed with the actress Jodie Foster - he survived but only just.

And in May of the same year, a gunman shot Pope John Paul II four times as he greeted crowds in St Peter's Square in the Vatican.

Evidence produced at his subsequent trial heard that Sarjeant had written: "I am going to stand and mystify the world with nothing more than a gun.

"I may in a moment become the most famous teenager in the world."

Having had his dreams of serving for Queen and country shattered, one can only assume it led him to make the Queen a sign of all that had held him back.

Friends reported that in October 1980 he had joined the anti-royalist movement.

In the months running up to his gun attack against the Queen, his fascination with guns had continued, and after failing to find ammunition for his father's revolver, or obtain a gun licence, he purchased two Colt Python revolvers - but crucially only capable of firing blanks.

Unemployed and lacking direction, Sarjeant travelled to London on that day looking for some of the infamy of the likes of Lennon assassin Mark Chapman.

He took up position on the corner of The Mall and Horse Guards, milling with the crowd of excited onlookers.

The Queen, 55 at the time, was riding side-saddle on her beloved horse Burmese - an imposing black police service steed which the Queen had ridden during the parade every year since 1969.

As she came into view, Sarjeant knew his moment had come.

He pulled out his revolver, held it with both hands, and fired six shots at the Queen. He was just a matter of metres away.

The cracks of the gun spooked the Queen's horse and others around it.

The BBC TV commentator at the time, covering the event live, remarked: "Hello, some little disturbance on the approach road."

Remarkably, the Queen swiftly brought the horse under control and as the guard around her closed ranks, a melee erupted where the shots had been fired.

St John's Ambulance staff member John Heasman, who was on duty at the scene, now 76, was the first man to grab the gunman.

He told KentOnline: "I didn't know at the time it was blanks in the gun. I just turned round and saw the gun being fired to my left, just over my shoulder.

"So I just turned around and grabbed him and pulled him towards me. There were people hitting him with umbrellas and shouting 'you're trying to kill our Queen' at him.

"He had a big rosette on his coat with Charles and Diana on it. He'd been there since 6am that morning. No-one thought anything of him until he fired the shots."

"I just turned round and saw the gun being fired to my left, just over my shoulder."

Alec Galloway, then 37, and a Lance Corporal in the Scots Guards was at the scene.

He would later remember: "I heard about six shots which I knew were close to me.

"I looked round to the right and there was this gunman pointing straight at the Queen and the shots going off.

"It all happened so quick. All I wanted to do was grab this man by the hair and pull him over the barrier.

"I felt sheer anger as I reached for him. I used all my strength to pull him over the barrier and knock the pistol to the ground.

"Don't go to the Trooping of the Colour today because there is an assassin waiting outside to kill you..."

"I got him over and was then able to control him with my boot. Then the police came in and took over."

The Queen was completely unhurt - and even drew admiration for the remarkably cool way she had regained control of her startled horse.

Reflecting on the incident years later, Prince Charles would say: "She's a marvellous rider; she has a marvellous way with horses.

"She's made of strong stuff, you know."

Wrestled to the ground, Sarjeant was bundled into a police van and driven off as the crowd around him turned increasingly ugly.

He was swiftly charged under the Treason Act of 1842 - creating a little of the history he craved by becoming the last person to be charged under the Act for "wilfully discharging at the person of Her Majesty the Queen a blank cartridge pistol with intent to alarm her".

Appearing in court a few months later, he admitted firing the gun at the Queen - and apologised for his actions.

"Don't go to the Trooping of the Colour today because there is an assassin waiting outside to kill you."

"I have little doubt that if you had been able to obtain a live gun or live ammunition for your father's gun you would have tried to murder Her Majesty..."

But the judge at the time had little sympathy.

In sentencing him to five years, Judge Geoffrey Lane told him: "I have little doubt that if you had been able to obtain a live gun or live ammunition for your father's gun you would have tried to murder Her Majesty.

"You tried to get a licence. You tried to get a gun. You were not able to obtain either.

"Therefore, for reasons which are not easy to understand, you chose to indulge in what was a fantasy assassination."

He added: "The public sense of outrage must be marked. You must be punished for the wicked thing you did."

Sarjeant appealed the sentence but it was rejected.

Speaking after the case, his grandmother said the act had been "out of character" for the teenager, who she described as "gentle" and who "wouldn't hurt a soul".

He would spend the majority of his incarceration in HMP Grendon - which was then a prison with a psychiatric unit - in Buckinghamshire.

It is said he wrote a letter personally to the Queen (his previous warning before the attack had arrived three days after the incident) apologising for what he had done. Unsurprisingly, he received no reply.

He was released in October 1984, at the age of 20.

He subsequently changed his name and started a new life. It is not known if he remained in Kent.

Alec Galloway would win a commendation for his efforts in wrestling Sarjeant to the ground.

St John's Ambulanceman John Heasman received a citation for bravery and was later invited to meet the Queen at Buckingham Palace, where she thanked him for his efforts.

The Queen would continue to ride in the parade, on her trusted Burmese, until the horse was retired in 1986.

At that point the Queen opted, instead, to travel in the parade sat in a carriage.

Sarjeant's desire for notoriety was short-lived. Today it is a name few remember.

Read more: All the latest news from Kent