By Caroline Gluck BBC Seoul Correspondent

It is cold and it has just started to rain. But that has not deterred a small group of South Koreans who are jogging in the countryside.

As they run, they shout out that they are determined to stop smoking.

They have each paid $200 to take part in a week-long retreat to help them stop.

I've been telling people, please don't smoke - you'll end up like me. I was healthy before, but now, I'm counting the days until I die

veteran comedian, Lee Joo Il

One of them, 64-year-old architect Kim Hak Yeul, explains why.

"I've been smoking nearly two packs for the past 40 years from the age of 20.

"I didn't know how harmful cigarettes could be when I was young."

"But recently, I've been more and more out of breath and feeling increasingly lethargic," he says. "I failed once, but this time I'm determined to succeed."

Cancer is a leading cause of death - with cases increasing by more than 10% over the last 10 years.

But South Korea has suddenly been gripped by an unprecedented wave of anti-smoking campaigns, prompting large numbers to quit.

Fear of cancer

For years, veteran comedian, Lee Joo Il, was dubbed the country's king of comedy.

Images of the chain-smoking comedian shocked the nation

But the chain smoker is now critically ill with lung cancer.

His recent television appearances have had a sobering effect on the nation.

The public was stunned to see Mr Lee, making an appeal from his hospital bed.

"I've been telling people, please don't smoke - you'll end up like me. I was healthy before, but now, I'm counting the days until I die."

Dr Kim Il Soon, from the anti-smoking lobby group, the Korean Association of Smoking and Health, said the images had a huge impact.

"When people saw pictures of the comedian, who is seriously ill, they were shocked and scared. All of a sudden they started to stop smoking. That was a good thing because lung cancer is a leading cause of death in Korea."

New legislation

On many streets, cigarette smokers gather in groups outside their offices.

More companies are making their buildings smoke free zones. Public buildings will soon follow suit.

Cancer is a leading cause of death in South Korea

New laws require restaurants, karaoke bars and internet cafes to establish non-smoking areas.

Suddenly, smokers like Won Kuk Chin are starting to feel as if they are social outcasts.

"I always have to go out for smoking - it is kind of irritating I think.

"These days, mass media say many things about no-smoking on television and many people want to stop smoking, but there are also people who don't want to stop smoking, and I'm one of them," he says.

It is also an unwelcome change as far as cigarette manufacturers are concerned.

"Cigarette sales have fallen by 12 percent because of the anti-smoking campaigns and a big tax increase. The market will be smaller in the future and we're trying to diversify our business," says Kang Yong Tak of the Korea Tobacco and Ginseng Corporation.

But he need not worry too much for now. Korea's restaurants and bars are still full of smokers.

Many South Koreans simply do not want to stop.

Old habits die hard - but change has already begun.