In this dark, damp and disused prison, spiritualist medium Derek Acorah has a difficult time coming to terms with allegedly hostile spirits. Fear gets the better of some female members of the crew and the director receives a cut to his head which cannot be explained by natural causes. The House Of Detention site is 300 years old. Built in 1845 , it soon to became London's biggest remand prison with up to 10,000 prisoners a year. Most of it was demolished in 1890 but the wardens residence and the entire underground level of the prison was left intact. Some underground cells became air raid shelters during the Second World War. In 1983 the doors were opened to tourists.