A former president of Imperial Tobacco Canada says the company's largest shareholder attempted to stop an effort to develop safer cigarettes.

Jean-Louis Mercier testified Thursday in the $2-billion class-action lawsuit against Canada's tobacco industry, which was launched by Quebec smokers.

Mercier said in the 1980s he came up with an idea after reading a report by the surgeon general of the United States. The report found tar and nicotine were among the cancer-causing agents in cigarettes.

The former president said he figured cigarettes would become safer if they contained lower amounts of the two carcinogens, so he spearheaded an internal study to try to develop a safer cigarette.

But Mercier said Imperial Tobacco Canada's largest shareholder, British American Tobacco, opposed the effort. He said BAT's chairman at the time sent a letter indicating ITC's research was risky.

According to Mercier, the letter said the research could be viewed as an admission to the public that smoking was unsafe.

Mercier said at the time, it was one thing for the surgeon-general to reach that conclusion, something else for a tobacco manufacturer to do the same.

He said ITC ignored the letter and continued the research, but Mercier offered no information on what eventually resulted from the study.

Mercier said at the time, tobacco companies had no credibility with the public, and even if a safer cigarette were developed, the industry never would have announced it outright.

He said, however, the scientific community might have been in a position to confirm such a finding, which in turn could have reassured customers.