Comparisons at nine hospitals revealed that there was a 17% year-on-year drop in heart attack admissions since the ban was introduced in March 2006.

It said the quality of air in pubs is now equivalent to that found outdoors.

Exposure to second-hand smoke north of the border is down by 40% among adults and children, the study added.

The findings will be presented to an international conference in Edinburgh on the ban organised by the Scottish Government.

They are based on scientific evidence collected from routine health data, as well as research projects undertaken by government scientists and Scottish universities.

Admissions to nine major Scottish hospitals were also compared in the year before and after the introduction of the ban.

Scotland's deputy chief medical officer, Professor Peter Donnelly, said they were proof that the ban had produced major health gains.

The primary aim of smoking bans is to protect non smokers from the effects of passive smoking

Professor Jill Pell

But Scottish publicans claim that many of the benefits could have been achieved without a ban and complain that bar sales have declined because of it.

More than 2,000 primary school children and adults aged between 18 and 74-years-old from 74 postcode areas took part in the research.

Professor Jill Pell, who headed the research team which made the findings, said: "The primary aim of smoking bans is to protect non-smokers from the effects of passive smoking.

"Previous studies have not been able to confirm whether or not that has been achieved. What we were able to show is that among people who are non-smokers there was a 20% reduction in heart attack admissions.

"This confirms that the legislation has been effective in helping non-smokers."

The main findings of the study were;

The ban has reduced second-hand smoke exposure in both children and adults.

Among primary school children, levels of a by-product of nicotine fell by more than a third (39%) following the ban.

In adults, cotinine levels fell by almost half (49%) in non-smokers from non-smoking households.

Non-smokers living in smoking households continued to have high levels of second hand smoke exposure in the home.

And the authors suggest that further action is urgently required to support smoking households to implement smoke-free homes and cars.

Ash Scotland chief executive Maureen Moore welcomed the research.

She said: "The ban on smoking in public places provides everyone in Scotland with effective protection from the harmful effects of second-hand smoke and was a courageous move taken by the Scottish Parliament.

"That decision has now been shown to be paying dividends for everyone living in Scotland."

After the Scotland banned smoking in enclosed public spaces, Wales and Northern Ireland followed suit in April 2007 and England did the same in July 2007.