An independent inquiry began today into the deaths of nearly 2,000 haemophilia patients exposed to HIV and/or hepatitis C through contaminated blood and blood products, described as the worst treatment catastrophe in NHS history.

"The purpose of the inquiry is to unravel the facts, so far as we are able, and to point to the lessons that may be learnt," former Labour MP Lord Peter Archer, who is heading the inquiry, said in his opening statement.

The public inquiry would suggest further steps to address the problems and needs of patients and of the bereaved families, he added.

The hearings concern the deaths of 1,757 haemophilia patients who received contaminated NHS blood and blood products. Many more are said to be terminally ill.

The inquiry's conclusions could not yet be predicted, Lord Archer said, adding: "Its impact will, however, depend crucially on the public perception of its value and we shall endeavour to make it a report worthy of high regard.

"Hopefully our findings may help to restore public confidence in the future treatment of patients.

"We trust it will also help those afflicted and bereaved to come to terms with the tragedy - knowing much more of how it came about."

A number of former ministers in the department of health and others able to give information have made contact, he said. "There is no hidden agenda. Neither I nor either of my colleagues will receive any remuneration."

The events, which took place between the early 1970s and the mid 1980s, have been described by fertility expert Lord Winston as "the worst treatment disaster in the history of the national health service".

The campaign on the patients' behalf has been led by Labour peer Lord Alf Morris, who was Britain's first minister for disabled people and is the president of the all-party parliamentary group on haemophilia.

He said that, of the 4,670 haemophiliac patients exposed to hepatitis C, 1,243 were also exposed to HIV and despite improvements in treatment for both viruses, only 2,552 patients with hepatitis C and just 361 with HIV are still alive.