Smoking bans reduce the number of people affected by passive smoking - with a drop in heart disease and heart attacks, research suggests.

A new review by experts from the Cochrane network found laws to ban smoking in public places do cut harm caused by passive smoking.

A team of Irish researchers funded by the Health Research Board in Ireland included 77 studies from 21 countries around the world.

In one study from the University of Liverpool, experts found that heart attack rates for men fell by just over 40% following England's smoking ban, which was introduced in 2007.

Some 33 out of the 44 studies reviewed on heart disease found a "significant reduction" following the introduction of smoking bans.

Researchers also found that the greatest reduction in hospital admissions for heart disease following smoking legislation was among non-smokers.

Professor Cecily Kelleher, from University College, Dublin, and author of the new review, said: "The current evidence provides more robust support for the previous conclusions that the introduction of national legislative smoking bans does lead to improved health outcomes through a reduction in second-hand smoke exposure for countries and their populations.

"We now need research on the continued longer term impact of smoking bans on the health outcomes of specific sub-groups of the population, such as young children, disadvantaged and minority groups."

Professor Peter Weissberg, medical director of the British Heart Foundation, said: "This review strengthens previous evidence that banning smoking in public places leads to fewer deaths from heart disease and that this effect is greatest in the non-smoking population.

"So, in public health terms, this has been a successful piece of legislation. Smoking is bad for smokers and for those around them.

"Reduced exposure to smoke leads to fewer fatal heart attacks."

He said the studies were observational and all had their limitations, but it would be difficult to study the effects of passive smoking in a more robust scientific way.

Simon Clark, director of the smokers' group Forest, said: "It's very difficult to draw definitive conclusions about the impact of smoking bans on people's health, especially non-smokers.

"It's true that the number of heart attacks went down in some places following the introduction of smoking bans, but in other areas the number went up or stayed the same.

"Clearly there are factors other than second-hand smoke that must be taken into account because most smoking-related diseases are multi-factorial, but smoking is an easy target.

"The fact remains that the largest ever study into passive smoking, published in 2003, concluded that the link between second-hand smoke and coronary heart disease and lung cancer may be considerably weaker than generally believed, although a small effect cannot be ruled out."

Penny Woods, chief executive of the British Lung Foundation, said: "These findings again show the public health benefits of banning smoking in public places. We continue to warn of the dangers of second-hand smoke, particularly on children, ranging from common colds to ear infections, asthma and meningitis.

"Despite this progress, the Government mustn't be complacent, however. Local smoking cessation services - the most effective way of helping people quit smoking - are at risk from local budget cuts."