The England smoking ban will save as many as 600 workers' lives each year because they will no longer be exposed to second-hand smoke, according to the Institution of Occupational Safety and Health (IOSH).
IOSH, a not-for-profit group that represents health and safety professionals, said the ban will have a major impact on improving the health of workers, reducing the associated risks of lung cancer and heart disease from passive smoke.
It said around three times as many workers die from passive smoking than die from workplace accidents.
The group also pointed to research in Scotland which revealed that workers are now exposed to 86% less smoke and that air quality in most Scottish bars is now comparable with average outdoor air quality.
Lisa Fowlie, IOSH president, said: "Obviously, having campaigned for this legislation, we'll be delighted to see workers across the UK protected from second-hand smoke.
"We've been concerned that England has had to wait 15 months longer than Scotland for the same protection for its workers and have urged employers to take action ahead of the official bans."
By Daniel Thomas