The "tragedy" of thousands of haemophiliacs who contracted life threatening diseases after being exposed to contaminated blood products should never have happened, an independent public inquiry was told yesterday.

The victims and their relatives gave emotional accounts about living with HIV and/or Hepatitis C following "the worst treatment disaster in the history of the NHS," according to fertility expert, Lord Winston.

Nearly 2,000 haemophiliacs exposed to the fatal viruses in contaminated blood or blood products more than 20 years ago have since died and many others are said to be terminally ill.

Successive UK Governments have refused to conduct a public inquiry into the events but today an independent investigation began hearing testimonies, and will later hear evidence from scientists, medical experts and MPs.

Sue Threakall, whose haemophiliac husband Bob died in February 1991, aged 47, after contracting HIV following the use of clotting agent Factor 8, told the inquiry: "I shouldn't actually be here today. None of us should.

"Not the inquiry panel who are doing this unpaid, not the widows and certainly not most people sitting here today who are having to battle on a daily basis just to stay alive.

"I say this for two reasons. The first reason is that this terrible tragedy should never have happened in the first place, it was wholly avoidable.

"Warnings were ignored, lessons were not learned and our community was lied to by the people it should have trusted most."

Mrs Threakall, 54, from North Devon added: "The second reason is that, given the gross incompetence - and worse - that happened in the first place, this should have been acknowledged by the Government of the time and dealt with honourably nearly a quarter of a century ago."

Haemophilia is usually an inherited disorder where the blood does not clot properly due to low levels of the clotting factors eight or nine.

Sufferers bruise easily and can have spontaneous internal bleeds, often in their joints and muscles.

In the 1970s a new method for producing clotting factors was discovered but, unlike earlier methods, plasma donations were taken from thousands of donors and pooled together - but if any of the sources were infected with a blood-borne virus the whole batch would be contaminated.

During this period some blood products came from America suppliers who paid what became known as "Skid Row" donors for their blood - people more likely to be infected with HIV and hepatitis C, according to the Haemophilia Society.

David Fielding, a 51-year-old haemophilia sufferer from Bolton, told the hearing how he needed a liver transplant in 1998 after he contracted hepatitis C, having taken contaminated Factor 8 in the late 1970s.

The married father-of-three, who works as a watch and clock repairer, said he became aware he was infected with hepatitis B in the 1980s and in June 1993 was informed he had hepatitis C, but stated that from medical records he had tested positive for the condition in 1981.

Asked by the inquiry panel if he was given any help financially or emotionally at the time, Mr Fielding replied that he received support from friends and family but was "appalled" by the treatment he received from the medical profession.

He said they were: "Never ever sympathetic to the viruses I was infected with. I cannot be more blunt than that. I hope somebody's got the guts to come here and say sorry."

The Haemophilia Society welcomed the inquiry, being conducted by Labour peer Lord Archer of Sandwell a former Solicitor General, but called on the Government to co-operate fully with it.

Haemophilia Society chairman Roddy Morrison said: "Nobody should have to go through the terrible traumas these people have faced.

"We want to ensure that the suffering of all those affected is recognised and that the NHS learns all the lessons from this tragedy, so that such events can never happen again."

The hearings began amid claims on the BBC's Newsnight programme that that Britain's doctors ignored warnings about using haemophiliacs to test out new blood products.

The programme claimed that from the early 1970s to the mid-1980s, 4,500 haemophiliacs in the United Kingdom were exposed to lethal viruses through blood products designed to help them.

The programme said that many official documents had "mysteriously disappeared", although the Government claimed some were shredded and others had not been released on grounds of commercial confidentiality.

One of the "most shocking" documents was a letter from the head of Britain's public health surveillance centre warning the Department of Health about the risk of Aids from Factor 8. But despite this Factor 8 imports continued to be used.

Lord Archer has said: "Our purpose is to unravel the facts, so far as we are able, and to point to lessons that may be learnt."

The hearing was adjourned to a date in May, yet to be set.