A leak of detailed prison blueprints has triggered a security alert at jails across England and Wales.
The layouts of more than 20 prisons have been shared on the dark web and are said to include location of cameras and sensors on perimeter fences.
It has sparked fears they may be exploited by criminals looking to smuggle drugs or weapons into prisons or aid inmates looking to escape.
The Ministry of Justice said ‘immediate action’ has been taken to ensure security across the prison estate.
Prison officials were informed via an internal email headed ‘security alert’, The Times reports.
It added that there was no intelligence to indicate who was behind the data breach but staff were told: ‘We must not be complacent to this risk.’
Ian Acheson, a former prison governor, told the newspaper: ‘If plans of high-security prisons have been leaked, co-ordinating that with open source material or Google maps could aid an escape after an attack on the exterior of the prison.
‘Much more plausible is using additional data to co-ordinate drone drops. But if you can deliver half a kilo of drugs via a drone then you can deliver weapons, explosives, whatever you want.
‘These places are wide open.’
He added: ‘The dark web is a marketplace for criminals and terrorists.
‘Detailed maps of our most secure institutions who hold enormous national security and organised crime risk should never end up as commodities for sale online.’
A senior prisoner service source told The Times the plans ‘only show how things are at a certain point’ adding that ‘we can change them to make sure security is in the right place’.
A Ministry of Justice spokesman said: ‘We are not going to comment on the specific detail of security matters of this kind, but we are aware of a breach of data to the prison estate and, like with all potential breaches, have taken immediate action to ensure prisons remain secure.’
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