Why are so many people still smoking?

For sure, many fewer of us light up than in 1948, when 82% of British men and 41% of British women were regular smokers. By 1974, 51% of men and 41% of women smoked; by 1992, it was 28% of us; in 2005, 24%. Since the Smokefree England legislation came into force in July last year, a further 235,000 people have given up with the help of NHS Stop Smoking Services. According to Professor Robert West's Smoking Toolkit Study, some 400,000 people have quit in the wake of the ban.

But that still leaves 23% of men and 21% of women, or just over 9 million people still smoking. They must know, or at least be aware of, the risks they are running: half of all regular cigarette smokers will die from their habit. Each year, some 114,000 smokers in the UK die from smoking-related causes. Smoking remains the single biggest cause of preventable deaths in Britain, killing more each year than alcohol, obesity, road accidents and illegal drugs together.

So the real question is: who still smokes? The answer, according to Beyond Smoking Kills, a report published today by the broadly endorsed pressure group Ash, is the poor. "The health inequalities involved are perhaps the most striking thing about smoking in Britain today," says Deborah Arnott, its president. "The more deprived your circumstances, the more likely you are to smoke."

According to Professor Martin Jarvis, a psychologist at University College London and a leading specialist in the field of smoking and health inequality, this is not a question solely of income: every main indicator of a lower socio-economic status is likely, independent of each of the others, to predict a higher rate of smoking. If your educational level is below the average, you are more likely to smoke. If you live in rented or overcrowded accommodation, you are more likely to smoke. Ditto if you do not have access to a car, are unemployed, or on state income benefit.