English smoking ban resulted in more cessation.

As many as 400,000 smokers have quit their habit as a result of England's ban on smoking in public places, according to a British cancer charity.

Cancer Research UK said the Smoking Toolkit Study it supports at University College London found that smokers were quitting in greater rates after the ban, which took effect July 1, 2007.

The study of 32,454 adults--including 8,604 smokers--taking part in monthly household interviews between November 2006 and March 2008 found a statistically significant acceleration in the rate of decline of smoking prevalence from 0.18 percentage points per month before the ban to 0.61 percentage points per month following the ban, according to data presented recently at the U.K. National Smoking Cessation Conference in Birmingham.

"These figures show the largest fall in the number of smokers on record," said Robert West of the health behavior research center at University College London, who conducts the study. "I never expected such a dramatic impact, and of course there are no guarantees that smoking rates will not climb back up again. But if the Department of Health can keep up the momentum this has created, there is a realistic prospect of achieving a target of less than 15% of the population smoking within the next 10 years."

West said the effect has been similar across age groups, sexes, and socioeconomic level. According to the study, 43% of smokers have tried to quit in the past year. On average, 6.4% of people who smoked in the previous year and 15% of those who tried to stop in the past year report being nonsmokers.

Quitters in the professional/managerial class are twice as likely to succeed as are those in the low-paid or unemployed class. Of those who attempted to quit in the lower-middle, middle, and upper-middle class, 7.6% were successful, compared with 5.5% in the working class, low-paid, and unemployed social grades, the study found.