British authorities and the country’s public health service knowingly exposed tens of thousands of patients to deadly infections through contaminated blood and blood products, and hid the truth about the disaster for decades, an inquiry into the U.K.’s infected blood scandal found Monday.

An estimated 3,000 people in the United Kingdom are believed to have died and many others were left with lifelong illnesses after receiving blood or blood products tainted with HIV or hepatitis in the 1970s to the early 1990s.

The scandal is widely seen as the deadliest disaster in the history of Britain’s state-run National Health Service since its inception in 1948.

Former judge Brian Langstaff, who chaired the inquiry, slammed successive governments and medical professionals for “a catalogue of failures” and refusal to admit responsibility to save face and expense. He found that deliberate attempts were made to conceal the scandal, and there was evidence of government officials destroying documents.

“This disaster was not an accident. The infections happened because those in authority — doctors, the blood services and successive governments — did not put patient safety first,” he said. “The response of those in authority served to compound people’s suffering.”

Campaigners have fought for decades to bring official failings to light and secure government compensation. The inquiry was finally approved in 2017, and over the past four years it reviewed evidence from more than 5,000 witnesses and more than 100,000 documents.

Many of those affected were people with hemophilia, a condition affecting the blood’s ability to clot. In the 1970s, patients were given a new treatment that the U.K. imported from the United States. Some of the plasma used to make the blood products was traced to high-risk donors, including prison inmates, who were paid to give blood samples.

Because manufacturers of the treatment mixed plasma from thousands of donations, one infected donor would compromise the whole batch.

The report said around 1,250 people with bleeding disorders, including 380 children, were infected with HIV -tainted blood products. Three-quarters of them have died. Up to 5,000 others who received the blood products developed chronic hepatitis C, a type of liver infection.

Meanwhile an estimated 26,800 others were also infected with hepatitis C after receiving blood transfusions, often given in hospitals after childbirth, surgery or an accident, the report said.

British Prime Minister Rishi Sunak is expected to apologize later Monday, and authorities are expected to announce compensation of about 10 billion pounds ($12.7 billion) in all to victims. Details about that payment are not expected until Tuesday at the earliest.

The report said many of the deaths and illnesses could have been avoided had the government taken steps to address the risks linked to blood transfusions or the use of blood products. Since the 1940s and the early 1980s it has been known that hepatitis and the cause of AIDS respectively could be transmitted this way, the inquiry said.

It said officials failed to ensure rigorous blood donor selection and screening of blood products, and when people were found to be infected, officials delayed informing them about what happened or gave them false assurances.

At one school attended by children with hemophilia, public health officials gave the children “multiple, riskier” treatments as part of research, the report added.

Langstaff said that while each failure on its own was serious, taken “together they are a calamity.”

Andy Evans, of campaign group Tainted Blood, told reporters that he and others “felt like we were shouting into the wind during the last 40 years.”

“We have been gaslit for generations. This report today brings an end to that. It looks to the future as well and says this cannot continue,” he said.

Diana Johnson, a lawmaker who has long campaigned for the victims, said she hoped that those found responsible for the disaster will face justice — including prosecution — though the investigations have taken so long that some of the key players may well have died since.

“There has to be accountability for the actions that were taken, even if it was 30, 40, 50 years ago,” she said.

(AP)