An investigation into one of Britain's most troubled jails, where men are sharing cells designed to hold one person, and inexperienced staff are struggling to cope. This leads to a multitude of other problems, including locking inmates up 23 hours a day, which turns them on to drugs or affects their mental health. Last year the Chief Inspector of HM Prisons declared emergency action was needed, prompting the Government to stump up £100million - but in spite of this, the Victorian prison appears on the brink of collapse