A former tobacco executive has admitted he helped to destroy research documents in the 1990s, when he was vice-president of legal affairs at Imperial Tobacco and a member of the firm's management committee.

Roger Ackman testified Tuesday in the $27-billion class-action lawsuit – the largest of its kind in Canadian history – which pits three cigarette companies against Quebecers harmed by tobacco or addicted to it.

Documents bearing Ackman's signature were projected on giant screens in the courtroom several times throughout his testimony.

'This all happened 20-some-odd years ago, and I have no memory of it'— former Imperial Tobacco executive Roger Ackman

Ackman acknowledged that he participated in the destruction of documents on numerous occasions.

"Why were they destroyed?" a lawyer for the plaintiff asked.

"Sir," Ackman replied. "This all happened 20-some-odd years ago, and I have no memory of it."

Ackman said he didn't remember why the documents were destroyed, who asked for them to be destroyed or what specifically was in the documents.

The suggestion from the plaintiffs is that Imperial Tobacco and the other defendants intentionally destroyed research showing tobacco is harmful.

Jean-Yves Blais is an addicted cigarette smoker and a plaintiff in the class-action suit. (CBC)

"There's a responsibility for tobacco — for any company, about their products," said Mario Bujold, the executive-director of the Quebec Council on Tobacco and Health. "If they know that there is a risk associated with their products, they have to inform their customers."

The next witness slated to appear is expected to testify about document destruction at a rival tobacco firm during the same time period.

Simon Potter will have a short walk from the witness box from his current position in the courtroom, where he is one of the lead lawyers defending Rothmans Benson and Hedges in the case.