Prison officers are being forced to deal with a 'toxic mix' of substance abuse and psychological disorders among an increasing number of seriously disturbed prisoners who should not be in jail in the first place.

These are the conclusions of the head of the government's prisons watchdog, Anne Owers, who said prison governors were 'on the edge of coping' with the crisis, with jails routinely operating at 24 per cent above capacity. Last month prisoner numbers rose to more than 76,000 for the first time.