This Real Story documentary follows an undercover reporter who goes behind bars to reveal the truth about life in a private prison.
This is the first time secret filming has taken place inside a UK jail.
The programme finds that a blind eye is turned to drug abuse, staff shortages compromise prisoner and guard safety and that, despite a number of vulnerable prisoners killing themselves, suicide watches go ignored.
At a time when more UK prisons are facing possible privatisation, Real Story's findings raise serious questions about the future of the British penal system.
Read more about the investigation:
Prison Undercover - The Real Story: BBC ONE, Wednesday 9 March, 2005 at 2100 GMT.