The new scanner – developed specifically for the prison service – allows staff to see instantly whether prisoners are smuggling in illegal contraband items, including drugs, weapons and phones.

Better quality images make it easier to detect contraband smuggled internally.

The level of detail has not been seen before in jails and surpasses anything else currently on the market.

HMP Winchester’s scanner picked up seven significant finds of contraband a day after being installed, including drugs and a phone.

The illegal items would have been destined for the prison wings, fuelling the illicit economy and potential violence.

HMP Winchester’s Governor, James Bourke, said: “This tool is so powerful in helping us combat a serious problem in prisons – illicit drugs.

“I hope the scanner will lead to less drugs being available in prisons, which I believe is essential if you want to drive prisoners in the direction of seeking treatment for their addiction.”

The installation comes as part of the Government’s £100 million package to improve security.

The investment will also fund new measures to tackle drugs and violence in prisons, including X-ray baggage scanners and metal-detection equipment, phone-blocking technology and a new digital forensics facility.

Prisons and Probation Minister, Lucy Frazer QC MP said: “The new technology here at Winchester is a vital part of our efforts to stem the flow of contraband into jails and allow officers to focus on rehabilitation.

“The scanners form part of our wider efforts to transform our prisons, creating 10,000 additional modern places and stepping up security to cut crime and ultimately better protect the public.”

Sixteen prisons have received the new scanners.

They are HMPs: Bedford, Birmingham, Bristol, Cardiff, Chelmsford, Durham, Elmely, Exeter, Hewell, Lincoln, Liverpool, Norwich, Pentonville, Preston, Wandsworth, and Winchester.