In the 1970s, a new treatment for haemophilia known as Factor VIII was prescribed on the NHS. It infected more than 1,300 people with HIV and more than 4,000 people with Hepatitis C. As a public inquiry into the scandal reopens, this investigative feature-length documentary for ITV's Bafta-winning Exposure strand offers a window into a tragedy whose scale and impact has been relatively understated in Britain.