Prisons are set to introduce bottom scanners in an attempt to stop prisoners smuggling mobile phones into jail.
The £6,500 chairs are being put in 102 jails across Britain aimed to tackle a surge in phone smuggling.
Prisoners will have to sit on the chairs, called Body Orifice Security Scanners (Boss), which bleep if they have a phone hidden inside them.
They are then scanned in a non-intrusive manner and can also be used to detect drugs and weapons.