Thailand's Bang Kwang prison, often dubbed "the Bangkok Hilton", is arguably the most infamous jail in the world. As the Thai authorities try to crack down on drug trafficking, This World gains the first ever access to the prison in which all inmates are serving sentences of more than 30 years, usually for drugs offences. The human stories from inside include a young British man struggling to stay sane and a death row prisoner pleading for a second chance. Producer: Chris Jones Editor: Karen O'Connor