A man is facing jail for converting replica submachine guns into lethal weapons which were later linked to some of Britain’s most notorious crimes, including the murder of Pc Sharon Beshenivsky.

Grant Wilkinson (34), of no fixed address, adapted replica Mac-10 guns in a garden shed at Three Mile Cross, near Reading, in Berkshire. The weapons were then distributed to criminals in London.

Officers found evidence of 11 guns at Three Mile Cross and buried at another location near Wooburn Green, Buckinghamshire.

Firearms from the gun factory have been linked to 51 shooting incidents dating back to August 2004, most of them in the Greater London area, with four in Birmingham.

One of the weapons was fired at the scene of the Bradford robbery in which Pc Beshenivsky was killed in November 2005. It did not fire the fatal shot.

Abdillh Jamma (22), from Birmingham, was one of the two men convicted of shooting the rookie officer during a bungled robbery in Bradford in November 2005.

A jury at Reading Crown Court convicted Wilkinson of a series of offences, including conspiracy to convert an imitation firearm into a firearm, conspiracy to sell or transfer firearms and ammunition, possession of a firearm with intent to enable another person to endanger life and possessing a prohibited firearm, namely a Mac-10 submachine gun.

Co-defendant Gary Lewis, aged 38, of Bourne End, Bucks was cleared of all offences.

Lewis said in his defence that he had been just an “odd-job man” for Wilkinson and knew nothing of the gun racket.

Wilkinson bought 90 blank firing Mac-10s from a registered gun dealer claiming they were to be used on the set of the new James Bond film.

He then set about converting the submachine guns into lethal weapons in two garden sheds behind a derelict property in Three Mile Cross.

Police said he was producing weapons on a commercial scale.