Detectives have revealed how they uncovered a makeshift factory that produced lethal “assassination kits” for organised crime groups.

Armed police arrested Ronald Knowles as he tried to burn a “treasure trove” of evidence in his back garden in Alfreton, Derbyshire.

The 64-year-old, who is now awaiting sentence, converted at least 33 replica pistols, and made enough bullets for a further 80 kits that were packaged with silencers and latex gloves.

The kits were sold by a notorious “drugs general” called Gary Hardy, from his home in Ravenshead, Nottinghamshire.

The makeshift factory was discovered as part of an investigation into Hardy by Nottinghamshire Police and the East Midlands Special Operations Unit (EMSOU).

Its details have now been released by the force after the conclusion of Hardy’s trial.

Det Ch Insp Mark Adas said officers moved in to make arrests after stopping a van in Measham, Leicestershire in August 2023.

They seized a box containing four “lethal” self-loading pistols, each individually packaged with a silencer, blue nitrile gloves and ten rounds of live ammunition.

“The bullets had been converted from blank firing to live. If discharged they would effectively expand on impact,” he said.

“These were lethal assassination kits. I call them that because they were individually packaged. The firearms were designed to kill. It is highly concerning.”

As armed officers moved into Knowles’ garden on Milford Avenue, drone footage captured the moment he emerged from an outbuilding with his hands up before being handcuffed in front of his bonfire.

Det Ch Insp Adas says that outbuilding contained lathes and a drill that the weapons collector used to make the silencers and convert the pistols and ammunition.

Police also seized throwing stars, machetes, crossbows and air weapons, and almost 1,000 rounds.

“With the amount of ammunition that we found, that was in our belief destined for conversion, another 80 assassination kits could have been converted,” said Det Ch Insp Adas.

“It was a significant find for us. This is the largest firearms manufacturing operation that I have ever seen, and to my knowledge one of the biggest we’ve seen in the East Midlands, if not wider”.

Knowles admitted serious firearms offences, and details can now be reported following the convictions of Hardy and two other men at Nottingham Crown Court.

Det Ch Insp Adas says Hardy, 61, was “very very dangerous” and led an operation that supplied lethal weapons to organised crime groups in the West Midlands and Essex.

“He was living in a nice address in Ravenshead, he had nice cars, he was leading a nice lifestyle but did not have any form of genuine employment to our knowledge,” the detective said.

“We will never know the true scale of how many lives have been saved as a result of us dismantling this operation, but it is significant”.

Gary Hardy first made headlines in September 2008 when he received a 20-year sentence in a major drugs trial at Nottingham Crown Court that had to be guarded by armed police.

That jury heard Hardy was one of three “drugs generals” in Nottinghamshire, and supplied heroin and amphetamines to dealers in Kirkby-in-Ashfield and Sutton-in-Ashfield.

He had a fleet of luxury cars and owned more than 40 properties as part of a string of businesses that made his earnings appear to be legitimate.

The court heard Hardy’s heroin supplies were smuggled into the UK in lorry tyres, and the profits were split with another Nottinghamshire “drugs general”, John Dawes, and his brother, Robert.

Robert Dawes was an international drug trafficker who was eventually arrested in Spain and has now been jailed in the Netherlands for ordering a hitman to kill an innocent teacher.

Now Hardy is due to be sentenced again at a date yet to be set along with Ronald Knowles and two other men who were convicted of firearms offences at Nottingham Crown Court last month.

One of those men is a 23-year-old drug dealer called Jason Hill.

Hill is already serving a life sentence for the “brutal and cold-blooded” murder of Owen Fairclough, whose body was found in Breaston in June 2023.

Six days after the discovery, officers searched Hill’s back garden in Derby Road, Risley, and found a hidden safe containing two guns, two silencers and two dozen 9mm bullets.

Nottinghamshire Police believe Hill obtained those weapons from Stephen Houston, 64, who lived in Corley, Warwickshire.

They say Houston was supplying Hardy’s assassination kits to members of the criminal underworld.

Knowles, Hardy, Houston and Hill will all be sentenced for possession of a firearm with intent to endanger life.

Knowles, Hardy and Houston will also be sentenced for conspiracy to convert a blank firing gun into a firearm, and conspiracy to sell or transfer a firearm.