Question to the Ministry of Justice:

To ask the Secretary of State for Justice, what assessment he has made of the practicality of installing Faraday cages in or around Britain's prisons in order to block illegal mobile telephone usage by prisoners; and if he will make a statement.

The illicit use of mobile phones undermines the safety and security of prisons. We are taking urgent and decisive action as the number of mobile phones and SIM cards seized continues to be too high.

We have invested £2million into detection equipment, including hand-held detectors and portable detection devices. We are also working with mobile network operators to deliver ground-breaking technology, which will stop mobiles smuggled into prisons from working.

Faraday cages block all radio signals from entering and exiting the spaces around which they are placed, which would compromise radio contact between prison staff, as well as other critical infrastructure.