By the mid-1970s, there were repeated warnings that imported US Factor VIII carried a greater risk of infection.
But attempts to make the UK more self-sufficient in blood products failed, so the NHS continued using foreign supplies.
Campaigners say haemophiliacs could have been offered an alternative treatment called Cryoprecipitate. This was much harder to administer, but was made from the blood plasma of a single donor, lowering the infection risk.
News has also uncovered evidence children were infected with hepatitis C and HIV after being placed on clinical trials of new treatments – often, without their family’s consent.
As late as November 1983, the government insisted there was no “conclusive proof” that HIV could be transmitted in blood, a line robustly defended by former health minister Ken Clarke when he appeared before the inquiry.
By the end of 1985, all Factor VIII products were heat-treated to kill the HIV virus.