The company wants to launch the cigarettes in 2006 but has kept the move secret, knowing it would infuriate anti-smoking groups.

Campaigners will dismiss any attempt to reinvent cigarettes as a less harmful product as a cynical ploy to recruit more smokers when the habit is already killing 114,000 Britons a year and the government is proposing curbs on smoking in public places.

Past claims to have found safer forms of smoking, such as the introduction of low-tar cigarettes in the 1970s, have all proven false. They were found to be as harmful as high-tar versions because people smoked more and took deeper drags.

Despite this history, BAT executives talk privately of �risk free� or low-risk cigarettes and suggest they might cut the chance of disease by as much as 90%.

John Britton, professor of epidemiology at Nottingham University, said: �Anything involving inhaling smoke is unsafe. These new cigarettes could be more like jumping from the 15th floor instead of the 20th: theoretically the risk is less but you still die.�

This weekend, BAT confirmed plans for the launch. David Betteridge, a spokesman, said: �They look and taste like normal cigarettes.�

Betteridge refused to divulge the name under which the cigarettes would be marketed or give details of how they worked. They were designed by scientists at the firm�s research centre in Southampton.

The cigarettes use �trionic� filters with three layers, each of which removes a different set of toxic compounds, while still allowing nicotine � the main addictive element in tobacco � to enter the lungs. The tobacco is also mixed with an inert �chalky� substance to retain more of the toxins in the ash.

BAT also claims to have improved the way it dries tobacco leaves to reduce cancer-causing toxins when burnt.

Even if they benefit smokers, such cigarettes would not prevent passive smoking. Deborah Arnott, director of Action on Smoking and Health, said: �Cigarette smoke contains about 4,000 different chemicals, many of which are toxic. These filters and tobaccos can make no more than a marginal difference.�

BAT will not be making any explicit claims that its cigarettes are safer, but will instead describe the product as �potentially safer�. It is likely to focus its advertising on the new technology, hoping that smokers will assume they are safer.

Betteridge said the company accepted there was �no such thing� as a truly safe cigarette and that the best way to minimise risk was to stop smoking.

JONATHAN LEAKE Science Editor

Source