The comes into force in summer 2007

The study revealed that a further 53% said they would try to quit the habit when the new laws are introduced.

MPs approved the legislation to ban smoking in workplaces, including pubs and clubs, last month.

The survey, commissioned by the charity No Smoking Day, showed that of 28 million smokers in the UK 22% said they would give up when the ban came in.

The government had predicted that the ban would result in 600,000 people quitting.

Knock-on effects

Ben Youdan, Chief Executive of No Smoking Day, said: "It proves that MPs were absolutely right to take the bull by the horns and vote for an outright ban on smoking.

"The ban was clearly the impetus people needed to help them decide to give up for good.

"The knock-on effects for their own health, and that of their children and partners, will be incalculable."

Simon Clark of pro-smoking group Forest is sceptical about the findings.

"I think they are living in cloud cuckoo land if they think a third of all smokers will give up.