Experts believe many lives may be saved
The smoking ban in England, introduced a year ago, has dramatically increased the number of people giving up the habit, it is claimed.
A survey suggests more than 400,000 people quit smoking as a result of the smoking ban.
Researchers say this could potentially help save as many as 40,000 lives in the next 10 years.
Separate research suggests the ban may have helped people with lung disease stay out of hospital.
The ban on smoking in public places was designed principally to protect people from secondhand smoke.
However, as in Scotland, which introduced the ban a year earlier, there are signs that it is providing the motivation for people to try to give up.
A survey of 32,000 people, found that smoking fell by 5.5% in the nine months after the ban, compared with 1.6% in the previous nine months.
On the basis of this, it was estimated that in excess of 400,000 gave up as a direct result of the ban.
Professor Robert West, who carried out the research at the Health Behaviour Research Unit, said he had not expected such a dramatic impact.
"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."
Cancer Research UK, which funded the research, said that the momentum now needed to be maintained.
Jean King, its director of tobacco control, said: "The results show smoke-free laws have encouraged smokers to quit.
"These laws are saving lives and we mustn't forget that half of all smokers die from tobacco-related illness."
Other reports suggested that cigarette sales had fallen sharply over the past year, with 1.93 billion fewer sold in England, and 220,000 fewer in Scotland, now in the second year of its ban.
Tobacco control pressure group ASH said that its own survey suggested that a majority of the public were now in favour of more legislation to clamp down on smoking, such as a ban on smoking in cars with children, and the removal of cigarette vending machines.
A separate survey, carried out by the British Lung Foundation, of more than 1,000 people with lung conditions, found that 56% said they have had fewer attacks of breathlessness from passive smoking in pubs and restaurants since the smoking ban was introduced.
Nearly two fifths (39%) said the ban had helped keep them out of hospital.
Dame Helena Shovelton, BLF chief executive, said: "The smoking ban has helped to save the lives of people with breathing problems by cutting down on their exposure to passive smoke."
The ban in Wales began a few months earlier than in England, but figures released by Plaid Cymru today suggested that heart attacks had fallen by 13% between October and December 2007, compared with the same period the previous year.