The Smoke free law in England has helped more smokers quit than ever before and will help prevent an estimated 40,000 deaths over the next 10 years - according to new research being presented in Birmingham tomorrow.

The Smoking Toolkit Study interviewed more than 32,000 people in England over the nine months before and nine months after last year's smokefree law took effect on July 1.The decline in smoking prevalence for the nine months pre-July was 1.6 per cent compared to an impressive 5.5 per cent in the nine months post July.

Based on the findings, researchers estimate that at least 400,000 people quit smoking as a result of the ban. There was no difference by age gender or social grade.

This is the first study in the world to examine in detail the impact on smoking rates solely from smokefree legislation without the influence of any other tobacco control measures.

Professor Robert West, Cancer Research UK's director of tobacco studies at the Health Behaviour Research Centre based at UCL, who carried out the study said: "These figures show the largest fall in the number of smokers on record. The effect has been as large in all social groups, poor as well as rich, smokers. 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 per cent of the population smoking within the next 10 years."

Jean King, Cancer Research UK's director of tobacco control, said: "The smokefree law was introduced to protect the health of workers from the harmful effects of secondhand smoke. These results show it has also encouraged smokers to quit. These laws are saving lives and we mustn't forget that half of all smokers die from tobacco related illness. We must do everything possible to continue this great public health success - we now need a national tobacco control plan for the next five years.

"The government consultation on the future of tobacco control runs from June until September. It provides an excellent opportunity to examine further steps we can take to reduce the devastating impact that tobacco has on the lives of many millions of people."

The study is currently funded by Cancer Research UK McNeil Pfizer and GlaxoSmithKline.