It was always going to be a difficult day in the witness-box for Prof Ian Temperley.
The former medical director of the National Haemophilia Treatment Centre faced some awkward questions over his decision to advise the board of the BTSB in June 1988 to continue supplying to haemophiliacs a product which was known not to be safe from hepatitis C and about which its manufacturers, Armour, if not the board itself, had serious safety concerns.
From today's viewpoint, the advice is hard to fathom for several reasons.
First, it entailed the BTSB signing a letter of indemnity absolving Armour from responsibility for the safety of the product - which exposed the State agency to a massive public liability risk.
Second, the advice was based on a philosophy which Prof Temperley admitted yesterday would not now be seen as "sound". That "philosophy" was that, given that most haemophiliacs had already been exposed to hepatitis C, there was no harm in exposing them to more of it.
Third, the advice was based on the factually questionable assertion that "virtually all" haemophiliacs had already been infected with hepatitis C. Prof Temperley admitted he had no means of confirming this, as an accurate test for the virus was not developed until 1989.
The doctor seemed happy to concede that, with hindsight, he would have given different advice. Ten or 15 years after the event, he said, one knew one could do better than "in the heat of the battle".
However, he maintained the advice at the time was "valid" in so far as he had been asked to choose between two products, the Armour Factor 8 or a new-to-the-market clotting agent using untested monoclonal technology.
The heat-treated Armour product, while known not to be safe from hepatitis C, had been shown to be free of HIV which, said Prof Temperley, was his "primary concern". The monoclonal product, while apparently safer in terms of hepatitis C, he noted, had a "suspicion" hanging over it in terms of HIV.
The witness's description of his predicament as an either/or situation, however, does not sit well with documentation shown to the tribunal. In a briefing memo from May 1988, the former chief executive officer, Mr Ted Keyes, lists three possible options available to the board, including pasteurisation, a method which proved to be safe from both HIV and hepatitis C.
Prof Temperley himself suggested another option at a board meeting in March 1988, that of solvent detergent technology which France and Switzerland had been using since 1986, and which the BTSB eventually adopted in 1989.
A further option available to the board was super-heat treatment - a technology which again proved successful in eliminating both the HIV and hepatitis C risks, and which had been operational in the UK since 1985.
Prof Temperley conceded it was true that other options were available. However, he said, a "major consideration" was the Government's stated aim of "self-sufficiency", which would have been undermined by importing super-heat-treated products from the UK.
Significantly, the board made special provision for infants and young children with haemophilia A who had not been exposed to potentially infectious products. These "virgin patients" were to receive a more costly pasteurised product under Prof Temperley's instructions.
However, as Prof Temperley admitted yesterday, no similar provision was made for "virgin" haemophilia B patients.
As far as he knew, he said, the only appropriate product on the market which was known to be safe from hepatitis C was British-made Factor 9. This was "most likely" to have been available. However, the possibility of using it "escaped us" at the time.
This was despite the directors of Britain's haemophilia treatment service, which Prof Temperley said was one of his main sources of advice, having recommended that the superheat-treated product be used.
In the absence of a safe product, BTSB-made Factor 9 produced from supernatant [a plasma derivative] returned by Armour was given to several haemophilia B patients, infecting three children and an adult with hepatitis C.