Designated no smoking areas give little to no protection from the dangers of inhaling tobacco smoke, a new study has claimed.

Researchers in Australia concluded such areas in clubs and restaurants at most halve the levels of second-hand smoke inhaled.

They say current regulations allowing smoking on premises are "ineffective" in protecting people from passive smoking - a conclusion backed by UK anti-smoking campaigners.

The research carried out in 17 social and gaming clubs in and around Sydney measured the amount of "environmental tobacco smoke" in smoking and non-smoking areas as well as outside.

Their findings, published in this month's Tobacco Control journal, showed levels of atmospheric nicotine and particulate matter, a potentially carcinogenic pollutant in smoke, were substantially (53 per cent and 52 per cent) lower in non-smoking areas.

But they also found the levels of reduction varied hugely and having a separate non-smoking room made little difference to the reduction in nicotine and particulate matter.

One of the authors, Professor Barbara Stewart of the Sydney Public Health Unit, said: "Non-smoking areas may provide some reduction in the level of exposure of individuals to environmental tobacco smoke. However, reduction may be marginal or trivial.

"Accordingly, such areas cannot be characterised as 'smoke free' and patrons occupying these areas do not achieve the protection they would experience were smoking not to occur on the premises."

The research was partly sponsored by the Cancer Trust New South Wales.

Campaigners Action of Smoking and Health UK (ASH) say employees are also at risk and recently wrote to all large hospitality firms warning them they could be sued over the effects of passive smoking.

Ian Willmore of ASH said: "This research confirms what we really knew, that designated smoking areas do not protect the public from second-hand smoke and of course, still leave employees exposed.

"This is further proof of the need for clear legislation preventing smoking in the workplace and in public places."

By Stuart Coles, PA News