Biometric technology which can identify visitors who may be trafficking drugs into prisons has been successfully trialled.

The technology, which includes iris scanning and facial recognition software, has been tested at three jails and is part of a wider crackdown on drugs entering prisons.

The trial comes against a backdrop of wide-ranging measures to tackle drugs and violence in prisons, including security scanners, drug search teams, digital technology to identify criminal kingpins and a Financial Crime Unit with the power to freeze suspect bank accounts linked to prisoners.

Intelligence work has identified a trend of prison visitors supplying illicit items to multiple prisoners and jails across the estate. These individuals have been difficult to track, however, as organised criminals may also falsify their identity documentation.

While some prisons have fingerprint recognition, most sites use paper-based verification, using documents like driving licences. In addition to being open to abuse by contraband traffickers, this system is slow and resource intensive.

The state-of-the-art biometric technology allows prison staff to identify visitors using applications based around document validation, iris scanning and facial recognition software.

It has been successfully trialled at HMP Hull, Humber and Lindholme. The Prison Service is now looking at how this, and other similar technology, could be used most effectively across the estate.

The machines highlight suspicious individuals, allowing staff to refuse entry and providing evidence that could be used in any subsequent Prison Service or police investigation. This will mean police and prison staff can better target the activity of those that seek to bring drugs into prison - disrupting their criminal networks.

It can also act as a deterrent, with one trial prison seeing a higher than usual ‘no shows’ rate at visits after attendees found out the software would be in operation.

“New technology is vital in our fight against the gangs that seek to cause chaos in prisons, and this biometric equipment has the potential to significantly aid our efforts,” said Justice Secretary David Gauke.

“It forms part of this government’s multi-million-pound investment to improve the safety and security of our prisons.

“Alongside our successful officer recruitment drive, measures like this will help make prisons places of rehabilitation where offenders can turn their lives around. This will cut reoffending and make the public safer.”

Last year more than 23,000 drugs and mobile phones seizures were made by prison staff, an increase of almost 4,000 from the previous year, showing the scale of the problem.