The "nanny state" mostly gets a pasting from critics who dismiss government efforts to make us fitter or slimmer or healthier as unwarranted intrusion into individual's lives.

Today, the critics get their comeuppance with research showing that nannying works. In the first year after the smoking ban was introduced in July 2007, the air in bars, restaurants and offices suddenly became sweeter – and more than 1,000 heart attacks were prevented.

Researchers who examined hospital statistics for England found there were 1,200 fewer admissions for heart attacks in the 12 months after the introduction of the smoke-free law. The researchers, from the University of Bath, adjusted the data to take account of underlying trends in admissions and variations such as seasonal temperatures and population size.

The finding demonstrates that in addition to smoking's long-term damaging effects, which are well known, it also has short-term effects, which are not. Exposure to even a small amount of smoke in the atmosphere can have immediate effects on the blood, causing it to thicken (as a result of platelet aggregation). Together with other changes affecting the blood vessels, seen within 30 minutes of exposure to smoke, they can lead to blood clots triggering heart attacks.

Several studies from around the world have shown similar, and sometimes larger, effects when smoking bans were introduced. But most have been conducted on populations much smaller than England's – 49 million – making the latest results among the most robust. The 1,200 heart attack admissions avoided is a 2.4 per cent reduction in total.

Michelle Sims, lead investigator on the study, said: "A 2.4 per cent reduction may sound small but, given the large number of heart attacks per year, even the relatively small reduction seen in England has important benefits."

The results, published in the British Medical Journal, follow figures showing the ban caused the biggest fall in smoking ever seen in England, with over two billion fewer cigarettes smoked in the first year. More than 400,000 people quit, the largest fall on record, which researchers predicted would prevent 40,000 deaths over 10 years, from lung cancer, heart disease and other smoking-related diseases.

The proposal to ban smoking in all enclosed public spaces including pubs, was first made by Sir Liam Donaldson when he was the Chief Medical Officer in 2003. He repeated his call in 2004, to the fury of the Health Secretary at the time, John Reid, who feared it would cost votes among smokers who liked a fag with their pint in his native Glasgow constituency.

After a prolonged political battle which split the government and inflamed critics of "nanny state" Britain, the law was enacted amid fears it could trigger civil disobedience and worse.

But opposition to the ban never materialised. By the end of the first year more than three out of four people supported the law, and compliance was virtually 100 per cent.

The London Health Observatory said the reduction in smoking-related heart attacks had saved the NHS £8.4m, equivalent to 11,700 cataract operations or 1,600 hip replacements.

Bobbie Jacobsen, director, said: "The introduction of the smoke-free legislation in England has resulted in almost 10,000 fewer bed days for emergency admissions due to heart attack."

Betty McBride, director of policy and communications at the British Heart Foundation, said: "Banning smoking in public places was a bold step and now we have evidence showing that it was absolutely right. Government should see this as a green light for further life-saving measures – going beyond the forthcoming ban on vending machines – to crack down on illegal tobacco smuggling and introducing plain packaging on cigarette boxes."

The smoking ban in England followed others introduced earlier in Scotland, Wales and Northern Ireland and many organisations had already banned smoking. This may have dampened the impact seen in the study, even though it was still significant, said the researchers.

The next targets?

* A ban on smoking in cars to protect children. Millions of children are exposed to second-hand smoke, which is worse in cars because of the confined space, says the Royal College of Physicians. Smoking is banned in cars carrying children in some states in the US, Australia and Canada.

* A minimum price for alcohol. The National Institute for Health and Clinical Excellence said it would discourage supermarkets from discounting cheap alcohol. No price was specified, but a 50 pence per unit of alcohol minimum would mean a bottle of wine would cost at least £4.50, and a pint of lager £1.14

* A fat tax, on fast foods and chocolate, to curb the obesity explosion. As smoking falls and obesity increases, experts predict the latter will come to be seen as more damaging than the former. Some want us to follow Romania's example which pledged earlier this year to introduce a tax on junk-food.