How the Ministry of Justice knowingly exposed hundreds to cancer-causing gas in Dartmoor prison

Exclusive: In the midst of a growing prison overcrowding crisis, men were piled into HMP Dartmoor. Officials had been warned parts of the ageing Victorian prison were filled with dangerous levels of a toxic gas linked to 1,100 lung cancer deaths each year. But in their desperate scramble for cells, the government appears to have been willing to gamble with the health of prisoners and staff, Holly Bancroft and Amy-Clare Martin report