One of the new adverts

The Cancer Research UK ads, which will run for three years, are being funded by the Department of Health.

They will urge smokers not to be fooled into thinking "low tar" or "mild" cigarette brands are less harmful.

The campaign, titled Death Repackaged, will also warn people that they are still at risk of developing cancer if they smoke, regardless of the type of cigarette.

Professor Gerard Hastings, director of the Cancer Research UK Centre for Tobacco Control Research at the University of Strathclyde, said: "The tobacco industry allows the belief that some cigarettes are 'milder' than others to persist.

"This provides smokers with a 'fall back' position with their addiction - naturally a smoker feels they are moving in the right direction by choosing a 'low-tar' brand and often this is done instead of quitting.

"The longer a smoker's addiction continues, the longer they'll be contributing to the tobacco industry's profits."

Low tar brands

Another image from the new campaign

A survey carried out two years ago suggested some smokers suffer from misapprehensions about low tar brands of cigarettes.

The poll of 780 women in London, who smoke low tar, light or mild cigarettes, found almost 40% believed they were doing themselves less damage than if they smoked regular cigarettes.

Three years ago, the government's top doctor warned that light or low tar cigarettes may be responsible for a significant increase in a rare form of lung cancer.

Sir Liam Donaldson, chief medical officer for England, said smokers of these cigarettes were under the misapprehension that those brands were not as bad for them.

However, smokers of low tar cigarettes generally puff more intensely, delivering more carcinogens and toxins to the peripheral lung area where the lung cancer adenocarcinoma develops.

Professor Martin Jarvis, from the Health Behaviour Unit at University College London, said: "Cutting back to a supposedly 'low-tar' cigarette can easily be a fool's paradise.

"Without realising it, people smoke these cigarettes more intensively, and end up getting just as much exposure to tar and other harmful smoke components as from regular cigarettes."

Death toll

Around 13 million Britons smoke. Half of all smokers will die prematurely.

There are 120,000 smoking-related deaths each year and smoking-related diseases cost the NHS �1.5bn annually.

Some three million people are exposed to second-hand smoke while at work.

The government has so far rejected calls to ban smoking in public places, including pubs and restaurants.

In July, Sir Liam urged ministers to introduce a ban. However, the Department of Health has consistently said it prefers a voluntary approach.

Last week, European Health Commissioner David Byrne said he would support a ban on smoking in public places.

From October cigarette packets will no longer say how mild or strong the contents are.