Research has revealed a 14% cut in rates of heart attack in Scotland, where the ban started a year earlier. Rates have dropped by about 10% in England in the year after the ban was introduced in July 2007.

Another study in Wales is expected to reveal similar results.

The research into heart attack rates in England is being led by Anna Gilmore of Bath University.

She said: “There is already overwhelming evidence that reducing people’s exposure to cigarette smoke reduces hospital admissions due to heart attacks.”

John Britton, director of the UK Centre for Tobacco Control Studies at Nottingham University, said: “We always knew a public smoking ban would bring rapid health benefits, but we have been amazed by just how big and how rapid they are.”

Ellen Mason, a senior cardiac nurse at the British Heart Foundation, explained why smokers and passive smokers have an increased risk of having a heart attack.

She said: “Exposure to cigarette smoke induces rapid changes in blood chemistry, making it much more prone to clotting. In someone who has narrowed or damaged coronary arteries, smoke exposure can tip the balance and cause a heart attack.”

Other western European countries have seen similar falls in heart attack rates after smoking bans. Figures showed France had a 15% drop in emergency admissions for heart attacks after a year, while both Italy and Ireland had an 11% reduction.