A haemophiliac exposed to contaminated blood over 20 years ago has given evidence at an independent inquiry.
Haydn Lewis will give evidence at the inquiry on Monday
Haydn Lewis, 50, from Cardiff, who has HIV and hepatitis C, said thousands have died after being given infected NHS blood in the 1970s and 1980s.
More than 1,700 patients given the contaminated blood have died, and many more are terminally ill.
The Department of Health said the government of the day had acted in good faith, given the information available.
It is thought nearly 5,000 people were exposed to hepatitis C and, of these, more than 1,200 were also infected with HIV.
Travelling to London to give evidence at the independent inquiry - which began in April - Mr Lewis emphasised that he would be speaking on behalf of many others affected by contaminated products used.
The former carpenter said his mission was to find out what went wrong as he said no one was being given an explanation.
"Nobody was given that job, ministers or the medical profession, and for 20 years now, there are now in total over 1,700 widows out there who to date have never had any clear explanation," he said before giving evidence.
"I'm not happy that the people who I feel were responsible haven't really had the integrity and decency to hold their hands up and say mistakes were made...
"We will try and address this properly and legally, just because they may have to swallow some bitter, embarrassing pill."
Roddy Morrison, chairman of the Haemophilia Society, said the implications of what had happened were "devastating".
"The particular sickening part of this is that the implications were greater than they need have been," he said.
Mr Morrison said the society wanted the "full truth" to come from the inquiry, and called for statutory representation for patients on boards which make policy decisions, as well as full compensation for those who had been affected.
Mr Morrison also called for "serious commitment" from the Government that it would ensure it would not happen again.
"We want to see recommendations that really make sure that the lessons have been learned," he added.
A spokesperson for the Department of Health expressed sympathy for those infected with HIV and hepatitis C.
However, she said the government of the day acted in good faith, relying on the information available at the time.
Mr Lewis knew from childhood he had the blood disorder haemophilia, which affects the blood's ability to clot.
He said he was tested for HIV in 1984, but was not told he had the virus until February 1985. He believes it was during this time that his wife - who also has HIV - became affected.
It was later in 1994, Mr Lewis was told he also had hepatitis C.