The barrel-vaulted ceilings cause an echo, the better to prevent prisoners from trying to talk to each other.

He also suggested that the suppression of the prison riot might prevent prisoners in other places from trying to revolt, and thus save lives.

Interior walls are studded every two inches with iron spikes to prevent prisoners from being able to escape.

The basket was a dunce cap designed to prevent prisoners from seeing one another.

He set stiff new rules to prevent prisoners from splitting their claims to get additional hearings.

Widdecombe told the Commons the restrictions were needed to prevent prisoners from escaping.

The cells and the corridors connecting them were designed to prevent prisoners from communicating with each other.

'Control' deals with the obligation of the Prison Service to prevent prisoners being disruptive.

All the others had been cut down to prevent prisoners from building escape rafts.

During the night, a strong light was constantly on, preventing prisoners from sleeping easily.