Detailed prison blueprints have been leaked, triggering a security alert at jails in England and Wales, it has emerged.
The leak, first reported by the Times, involves prison layouts being shared on the dark web in the last fortnight, prompting an investigation by the National Crime Agency.
The plans are understood to detail the location of cameras and sensors, sparking fears they will be exploited by criminals to smuggle drugs and weapons into prisons or to aid escapes.
The leak emerged after prison officials who work at the jails were sent an internal email titled “security alert” to inform them of the breach.
However, one Whitehall source played down the significance of the breach, saying cameras were regularly moved and could already be seen by drones. They said prison blueprints had been available on the internet for years and were visible on Google Earth.
In the alert, prison officers were told that the breach could affect the security of the internal fences, which have technology installed that raises the alarm if there are attempted breaches.
The staff memos reported that there had been a data loss which had led to “vulnerabilities” in these security systems. This meant there was a danger that members of the public had been made aware of information that put prisons’ perimeters “at risk”.
This could be from people “attempting to convey items into the establishment/aid an escape”, the email warned.
A government spokesperson said: “We do not comment on security matters.”
The prisons watchdog warned on Friday that security was not keeping pace with technology, saying drones could deliver guns into jails riven by drug-related gang wars amid an “inadequate” response from the Prison Service.
Charlie Taylor, HM chief inspector of prisons, told the Guardian that the surge in the use of large unmanned aerial vehicles was his “number one concern” and had increased the possibility that firearms would be used to settle turf wars or attempt escapes.
Dealing with the prison system in England and Wales is a top priority for the government, after it inherited a crisis of overcrowding and poor conditions from the last government.
No 10 signed off on emergency measures over the summer to deal with a lack of jail places, releasing thousands of prisoners early after they had served 40% of their sentences.
In September, five of the most senior former judges in England and Wales said “radical solutions” such as the earlier release of killers and rapists on licence should be considered to ease the prison overcrowding crisis.
They recommended a review at the halfway stage of the determinate sentences of all prisoners serving longer than 10 years. Other proposals include the release of all prisoners serving indeterminate sentences who are over tariff, and the removal of all those who are elderly, dying or who have dementia from prison.
Shabana Mahmood, the justice secretary, is undertaking an urgent independent review of sentencing legislation and practice.
