Dr Anne Gilmore and colleagues from University of Bath examined data on emergency hospital admissions in patients aged over 18 from July 2002 to September 2008. They found there were 1,200 fewer emergency admissions a year in the 12 months after the ban was introduced, equivalent to a fall of 2.4%.

Writing in the BMJ, the researchers said: 'Given the large number of MI events per year, even the relatively small reduction seen in England has important public health benefits.'

The researchers compared data from the five-year period before the ban on smoking in public places began on 1 July 2007 with data from the 12 months after its introduction. They adjusted their data to take into account changes in seasonal temperature and population size as well as underlying trends in admissions.