Former Huntingdon MP and Prime Minister Sir John Major will give evidence to the Infected Blood Inquiry on June 27.

The UK's largest-ever public inquiry is looking into evidence that 1,243 people with the blood-clotting disorder haemophilia were infected with HIV after being given Factor blood products. Most died from AIDS before effective HIV drugs became available in the late nineties.

Sir John will give evidence under oath at Aldwych House in London. His evidence centres on his time in the Treasury. He was Chief Secretary to the Treasury from 1987 - 1989 and Chancellor of the Exchequer from 1989 - 1990.

According to the campaign group, Factor 8, a letter written by Sir John in 1987 to the then health minister, Tony Newton, advised against "a sympathetic response" to infected blood product victims.

Factor 8 say he told Tony Newton that such a response could: "give rise to court action against the Government because of the implication of negligence".

Infected haemophiliacs and their families did bring a court action, but it took many years and caused much heartache. The eventual settlement of the HIV haemophilia litigation in December 1990, shortly after Sir John became Prime Minister, is still subject to much controversy.

The Factor 8 group and others who have been impacted by the scandal, say victims were encouraged to sign away their rights to sue for HIV and Hepatitis C virus (HCV) for as little as £20k.

During the 1970s and 80s thousands of NHS patients were infected with life-changing, chronic diseases, including HIV and Hepatitis, after receiving donated blood and blood plasma products.

Most of those infected suffered from a genetic bleeding disorder called haemophilia, which results in the blood not clotting properly. In the 1970s, freeze-dried clotting agents called Factor 8 and Factor 9 became widely available.

These Factor concentrates revolutionised haemophilia treatment because they could be stored at home, allowing patients to self-infuse.

We know now that much of the donated blood used to make Factor products was contaminated. It is estimated that more than 1,300 people in the UK were infected with HIV, more than 4,000 with Hepatitis and at least 1,500 people have died, and that figure continues to grow. Some were co-infected with Hepatitis and HIV.

Many also suffered the social stigma of a HIV diagnosis at a time when there was mass public hysteria, prejudice and ignorance around this new virus sweeping the world. Decades of campaigning by victims and their families reveals a deeply appalling episode in our history

People using these products began to be infected with Hepatitis from 1973 when the products were first licensed for use in the UK.

Throughout the 1970’s Factor concentrates began to be used more often and by the late 1970’s they had become the most commonly prescribed treatment for Haemophilia. Before this time, the previously most prescribed treatment was Cryoprecipitate which was safer because each unit was derived from the blood-plasma of just one donor.