A man will appear in court after National Crime Agency officers uncovered what they believed to be a specialist factory in south London for converting blank-firing guns into lethal weapons using 3D printed parts.

Evan Girdlestone, 47, from Colliers Wood, will appear before magistrates in Croydon charged with offences under the Firearms Act.

He was arrested in Croydon on Thursday morning and, in the car, officers from the NCA’s Armed Operations Unit recovered what was believed to be a functioning converted weapon and magazines filled with 9mm ammunition.

Investigators later searched an industrial unit in the Lombard Road area of Merton and found an array of tools and machinery, including parts used in the manufacture of weapons and ammunition, blank firers, more than a hundred rounds of live ammunition, around a thousand rounds of blank-firing ammunition, and three potentially functioning converted weapons.

Officers also found several 3D printing machines suspected of being used to print component parts for converted weapons.

The seized weapons are being assessed and analysed by forensic experts.

Girdlestone has been charged with possession of a firearm, namely a handgun contrary to Section 5 of the Firearms Act 1968 and possession of ammunition contrary to Section 1 of the Act.

Debbie Palmer-Lawrence, from the NCA’s Armed Operations Unit, described it as a “significant operation” and said stopping converted weapons from reaching criminals was a priority for the NCA.