Passive smoking kills more than 11,000 a year in the UK - much higher than previously thought, a study shows.
Doctors want to see a complete smoking ban in public spaces
The British Medical Journal study also gives a figure for people dying from second-hand smoke in the workplace - 600 a year - for the first time.
Leading doctors said the findings proved a complete ban on smoking in public places was needed.
But smoking lobby group Forest said there was still little hard evidence of the effect of passive smoking.
November's Public Health White Paper proposed a ban on smoking in public places with the exception of pubs which do not serve food.
At the time much of the medical establishment criticised the proposals for not going far enough.
But doctors have thrown their support behind Liverpool's bid to introduce a complete ban in all workplaces, which is due before the House of Lords later this month.
Researchers at University of Queensland in Australia compiled the report from UK databases of causes of death, employment, structure of households and levels of active smoking and exposure to passive smoking.
They found 2,700 deaths among people aged 20 to 64 could be attributed to second-hand smoke and 8,000 in 65-year-olds and over.
A further 617 deaths were caused by workplace passive smoking, including 54 in the hospitality industry.
Smoke free policies
Report author Konrad Jamrozik said: "It is clear that adoption of smoke free policies in all workplaces in the UK might prevent several hundred premature deaths each year."
Previous studies have put the figure much lower. The British Medical Association estimated it was 1,000 a year three years ago but said the latest study was a much more comprehensive guide to the problem.
BMA chairman James Johnson said: "As doctors we see first-hand how second-hand smoke kills.
"I don't know how John Reid [the home secretary] can continue to serve the public half-measures on health. We need a total ban and we need it now."
And Royal College of Nursing president Sylvia Denton said a complete ban would "save lives".
"Given the unarguable scientific evidence, it is now essential that policies are put into place to protect the public from exposure to other people's smoke.
"No-one is denying a smoker rights, but as nurses we have to be advocates for everyone's health."
Emma Cooney, of the British Heart Foundation, said: "The evidence supporting a smoking ban in all public places is so strong that there is widespread agreement among the medical community, and no room left for scientific debate.
"There is no logic in the current White Paper proposal to only ban smoking in those pubs that do not serve food."
Simon Clark, director of Forest, said the discrepancy between the latest figures and those put out previously by the BMA demonstrated that nobody could actually quantify the impact of passive smoking.
"These are guesstimates, statistical projections that bear no relation to reality what so ever," he said.
"We keep asking the BMA for hard evidence of the health impact of passive smoking, and they simply cannot provide it.
"It is fraudulent to call for a total ban on smoking in all public places based on statistical projections, and not hard evidence."