A recovering drug addict went to a High Street chemist to collect his methadone script and left behind what appeared to be a shopping list, a court heard.

But when the shop assistant looked at it she was horrified to see it contained details about the production of ammunition.

The police were informed and when armed officers raided Geoffrey Mayne’s home in Ashford they discovered a semi-automatic rifle and 57 rounds of expanding ammunition.

They also found documents headed Kent War Forces and an ID card in the 24-year-old’s name as a self-styled Colonel and an application form.

Prosecutor Danny Moore said the ideology on the documents were of great concern as it referred to targets such as Muslims and the terrorist organisation Isis. It spoke of a paramilitary force and called members “warriors”.

Maidstone Crown Court was told Mayne went to Boots chemist in Ashford on July 20 this year and while collecting his methadone script asked for the flammable liquid acetone.

He told the sales assistant he needed it for cleaning pipes. After he left with the acetone the piece of paper containing details of ammunition was found.

When officers went to his home in New Rectory Lane, Kingsnorth, he would not let them in. They returned three days later with a firearms warrant.

In his bedroom they seized a .22 Ruger rifle from an unlocked cabinet with a magazine in it containing five live rounds of expanding ammunition and a silencer attached. There were also component parts to make ammunition.

“He was plainly making ammunition and experimenting with making weapons,” said Mr Moore. “There was an empty magazine case and partly completed shotgun cartridges.”

There was no evidence that Kent War Forces, referring to a “God-given right to defend Kent and bear arms”, actually existed.

Judge Julian Smith said it was “unnerving and profoundly unsettling” and asked if there was any evidence it had gone beyond writings in his bedroom.

Mr Moore said: “There is no evidence beyond that. The counter terrorism squad looked into him and no further work was done around that issue.

“But he certainly is capable of causing substantial injury and damage to human life. One area of concern is the lack of explanation. There is a disinclination to provide information about motivation.”

Judge Smith said: “If there is the slightest evidence such an organisation existed and was subscribed to by a number of people it would be altogether more serious.

“I bear in mind his professed intentions and ideologies. It may be part of his fantasy world.”

Mayne admitted possessing a firearm without a certificate, a detachable sound moderator (silencer), a cartridge and three offences of possessing rimfire expanding bullets.

John Fitzgerald, defending, said: “What we have here is a 24-year-old person who on the face of it is has the wherewithal to cause serious harm.

“There is no suggestion he has done anything about it. He doesn’t suffer from any mental illness.”

Mayne had an interest in history and warfare firearms and it was his favourite subject at school, said Mr Fitzgerald.

He hoped to set up a business online he was genuinely interested in. He was entitled to work on antiques and ammunition.

“It was a combination of his curiosity and an interest in this area that led him to have these items,” said Mr Fitzgerald. “He had it for eight or nine months.

“So far as Kent War Forces is concerned, it is a concept and idea. He saw it as a potential business for security work and military contact.

“Expanding ammunition is profoundly dangerous and unsettling and unnerving" - Judge Julian Smith

“For my part, I accept this is pie in the sky stuff. But in his relatively introverted existence and naivete he somehow had a vision of a grand business where he would employ people.

“We have writings on paper which I would submit is rubbish really that he is carrying around.”

Jailing Mayne for the minimum sentence of five years for possessing expanding ammunition without a certificate, Judge Smith said: “You have not been entirely straight forward.

“Kent War Forces is probably a creation of your own – part fantasy and part ambition. It becomes worrying and potentially dangerous.

“All of it is unsettling. The ambition is to engage in conflict with organisations such as Isis. It is difficult to follow logically. It is apparently compulsive and entirely unusual.

“I am concerned about you and your attitudes and apparent ambitions. I have difficulty with you because I don’t trust you to speak the truth.

“Expanding ammunition is profoundly dangerous and unsettling and unnerving.”