Publishing her annual report yesterday, the chief inspector of prisons, Anne Owers, warned that poor conditions in overcrowded jails could lead to legal challenges under the Human Rights Act.

"There are degrading conditions in which we should not be keeping people...I would not be surprised if cases materialise under the act," she said.

Owers warned of the "debilitating and chilling effect" of jail overcrowding and questioned whether the government's spending plans would do enough to prevent a crisis in the prison system.