A conflict in evidence regarding the late Mr Sean Hanratty's role in the selection of blood products for haemophiliacs emerged at the tribunal yesterday.
Prof Ian Temperley said the former BTSB senior technical officer and shareholder in AccuScience, a company which supplied the blood bank with products, was "ubiquitously" involved in discussions regarding concentrates.
The doctor said he did not want to say Mr Hanratty was "definitely a person who made the choice" as to which product should be used.
However, he said, "clearly" the board official played some role and had some influence over the thinking of doctors, although "I'm not quite sure just how formal that was".
Prof Temperley's evidence directly contradicts that of Mr Ted Keyes, the former BTSB chief executive, who said last year that Mr Hanratty would not have had any role in product selection.
Mr Hanratty was a founder and co-director of Accu-Science, which supplied commercial concentrates to the board from 1984 onwards as an agent for the pharmaceutical firm Cutter. He claimed to Mr Keyes that he had disposed of his shareholding in 1982 when he realised there was a potential conflict of interest.
His withdrawal from directorship, however, was not officially registered until 1991 after an internal BTSB inquiry.
Prof Temperley said he could not recall knowing anything about Mr Hanratty's link with Accu-Science in 1984 when the doctor was arranging the purchase of Cutter concentrates. His knowledge of the connection came later, he said.
Asked whether Mr Hanratty was involved in the decision that year to drop Travenol as a supplier of concentrates despite the fact the company had started to heat-treat its products to guard against HIV, Prof Temperley replied he could not recall or comment further other than saying "he was thereabouts all the time".
