The public inquiry into the infected blood scandal, known as the biggest treatment disaster in NHS history, is due to publish its findings.
More than 30,000 people were infected with HIV and hepatitis C from 1970 to 1991 by contaminated blood products and transfusions.
About 3,000 of them have since died - many haemophiliacs given infected blood products as part of their treatment.
Prime Minister Rishi Sunak will reportedly issue an apology on Monday.
Chairman Sir Brian Langstaff will deliver his findings after the Infected Blood Inquiry took evidence between 2019 and 2023.
Two main groups of people were caught up in the scandal.
One was people with haemophilia, and those with similar disorders, who have a rare genetic condition which means their blood does not clot properly.
In the 1970s, a new treatment was developed to replace the missing clotting agents, made from donated human blood plasma.
But whole batches of the treatments - Factor VIII and Factor IX - were contaminated with deadly viruses.
Some of the treatments were imported from the US where blood was bought from high-risk donors such as prison inmates and drug-users.
The second group affected include people who had a blood transfusion after childbirth, accidents and during medical treatment.
Blood used for these patients was not imported, but some of it was also contaminated, mainly with hepatitis C.
whether the victims have been supported enough
whether there were attempts by the government or NHS to conceal what happened
what more should have been done to prevent people becoming infected, including whether screening could have been introduced sooner.
Sir Brian's two interim reports, published in July 2022 and April 2023, made recommendations about compensation for victims and their families.
The government has said it accepts the "moral case" for compensation, and interim payouts of £100,000 each have already been made to about 4,000 survivors and bereaved partners.
Ministers have promised to address the issue of final compensation once the inquiry's report is published. The total cost is likely to run into billions.
On Sunday, the Conservatives and Labour both committed to compensation for victims, no matter the outcome of the general election expected later this year.
Shadow health secretary Wes Streeting told Laura Kuenssberg there was a "rare moment of consensus", as Defence Secretary Grant Shapps agreed families had been let down "over decades".
The Tainted Blood campaign group chairman, Andy Evans, who was infected with HIV and hepatitis C as a child through his haemophilia treatment, said publication of the report would be a "defining" moment after decades of campaigning.
"This is where we pin our hopes, really - we don't have anywhere else to go after this," he said.
"From the very beginning, victims have been gas-lit by government saying that the treatment was the best available and every decision was made with the best intention and with the best information they had available at the time.
"Through the course of the inquiry, that's proven to be false. The testimony that we've heard, both from victims and from people in office and the NHS, has shown that that wasn't true."
During the four-year inquiry, victims and their families have given evidence alongside former and current ministers, including Lord Clarke, who was health minister in the 1980s, and the current chancellor, Jeremy Hunt, who also gave evidence in his former role as health minister.
Speaking to the BBC's Westminster Hour on Radio 4, Labour's Dame Diana Johnson, the leading MP campaigning in parliament for the victims of the scandal, said many of the victims and their families were "apprehensive" and "worried" ahead of the report's publication, as "so many times before they've been let down".
She said those affected by the scandal had had to "battle and battle" against successive governments who had denied any wrongdoing since the 1980s, and that compensation for them would be "an acknowledgment of what the state did to those individuals and their families".
She said there was hope that their main questions - "Why was this allowed to happen and why was it covered up for so many years?" - would be answered by Sir Brian.
Speaking on the same programme, former Business Secretary Sir Jacob Rees-Mogg said, "If the state has killed people it has got to pay the price", and that the government "should not shy away from it being expensive".
He added that the scandal demonstrated a "defence mechanism within the institutions of the state which we need to break down".
"For some reason there is a desire to cover up the mistakes made by long since passed government to no benefit of anybody who is currently in government...I do not understand why the state is not more open to saying yes mistakes were made."
On the issue of compensation for victims and their families, the Conservative MP said: "People deserve this compensation. This is one of the most important bills the government will pay."
Campaigners have also been critical of how long it has taken to get a public inquiry.
In other countries that faced contaminated blood scandals, including France and Japan, investigations into the medical disasters were completed many years ago.
In some cases, criminal charges were brought against doctors, politicians and other officials.
In the UK, a private inquiry in 2009 - funded entirely by donations - lacked any real powers, while a separate Scottish investigation in 2015 was branded a "whitewash" by victims and their families.
In 2017, following political pressure, then-Prime Minister Theresa May ordered a UK-wide public inquiry.
The findings are set to be presented at 12:30 BST.