When the ban on smoking in public was introduced in July, eradicating the tobacco haze that had hung over England's pubs and clubs for a more than a century, sceptics argued the only impact would be to drive down bar takings.
Three months later the first survey of the effect of the legislation has revealed dramatic improvements in air quality – and a boost to trade. Smoke-free premises have been good for health – and business.
Researchers from the Tobacco Control Collaborating Centre in Warwick visited 59 establishments around the country in June and again in August, including bars, pubs, clubs, bingo halls, betting shops and cafes. They found staff exposed to harmful levels of second hand smoke had fallen by 95 per cent.
"Small particles" in the air from cigarette smoke fell from near-hazardous levels in June to levels similar to the outside air in August and staff had four times less cotinine in their blood, a by product of nicotine.
The researchers calculated that on average the exposure of staff had dropped from the equivalent of smoking 190 cigarettes a year to 44 cigarettes after the ban was introduced.
In each business, the owner, four employees and four customers were interviewed and their attitude and behaviour towards the new law assessed.
Hilary Wareing, a co-director of the Tobacco Control Collaborating Centre, said: "This study proves ... that smoke-free workplaces are helping to improve the health of the nation's hospitality workers."
Businesses have also prospered since the law change. In June, more than half of the owners said the change would damage their trade. In August, 70 per cent said there had been a positive impact or it had made no difference.
Elspeth Lee, the senior tobacco control manager at Cancer Research UK, which funded the study to be presented to the National Cancer Research Institute conference in Birmingham today, said: "We won't see a reduction in cancer rates for some years to come but the short-term health gains we have seen are very encouraging. As one of the largest countries in the world to adopt smoke-free legislation to date, we hope these results will demonstrate to other nations that this legislation ... has almost immediate health benefits."
The research is published as a new law comes into force raising the legal age for buying tobacco from 16 to 18. Health campaigners welcomed the move, saying it would be easier for retailers and customers to follow the law. The Department of Health hopes the move will cut the number of teenage smokers and has promised a crackdown on retailers who flout the law. Shop-owners could face fines or prosecution if they sell tobacco to those under-age.
A spokesman for the British Retail Consortium said it supported a move to bring tobacco in line with alcohol, fireworks and glue.
Simon Clark, the director of the smokers' lobby group Forest, said it supported measures to discourage children from smoking, but accused the Government of sending out mixed messages. "You're considered old enough to have sex at 16, drive a car and join the Army at 17, but the Government doesn't want you to smoke until you're 18," he said.