Claims by tobacco companies that plain packaging will have no effect on smoking are based on "weak evidence" and include studies commissioned by the industry, researchers have said.

Submissions to the Government by Imperial Tobacco, Japan Tobacco International, Philip Morris and British American Tobacco contained poor quality studies that had not appeared in peer-reviewed journals or were commissioned by the tobacco sector, they said.

Experts from the University of Bath and the UK Centre for Tobacco and Alcohol Studies, writing in the journal BMJ Open, found that only 17 of 77 pieces of data submitted to the Government by the industry addressed the impact of standard, plain packs on smoking.

None of the 17 were published in a peer-reviewed journal and 14 of the 17 (82%) were either commissioned by or linked to the tobacco industry.

This link was not stated in most of the company submissions to the Department of Health's public consultation on the issue, the researchers said.

They added that evidence cited by the tobacco industry was also of significantly lower quality than other available evidence.

Overall, the submissions showed that tobacco firms rejected the conclusions of a systematic review, commissioned by the Department of Health, that there was "strong evidence" that plain packaging would reduce the appeal of tobacco products.

A final evidence review chaired by Sir Cyril Chantler will be published next month.

Professor Anna Gilmore, from the University of Bath, said: "Historically, the tobacco industry manufactured evidence to cast doubts on the health impacts and addictiveness of its products. Now it is manufacturing evidence on the impacts of policies that could threaten its profits.

"By paying for evidence which created doubts about the impact of standardised tobacco packaging, the industry successfully delayed the policy.

"As a result, between July 2013, when the Government put plain packaging on hold, and March 2014, when the Chantler review will be completed, an additional 148,554 children (4,951 classrooms full) will have started smoking."

Alison Cox, Cancer Research UK's head of tobacco policy, said: "Once again, the tobacco industry has played fast and loose with the evidence to put its profits before the nation's health.

"This report proves that we need more transparency about sources of evidence to stop the tobacco industry from using its vast resources to influence policy making.

"During the final evidence review it's critical that the Government sees past the industry's misdirection, and only considers high quality evidence."

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