Allen Carr, an anti-smoking campaigner who helped millions quit by showing how he kicked a 100-a-day habit, has died from lung cancer.

The 72-year-old claimed to have helped 25 million people to give up, including leading figures such as the Virgin boss Sir Richard Branson, the actor Sir Anthony Hopkins and the footballer Gianluca Vialli.

He sold millions of books on giving up smoking and opened 70 clinics in 30 countries. He was diagnosed with inoperable cancer in July and died in his sleep at his home near Malaga, Spain, with his wife and daughters at his bedside, his spokesman said yesterday.

"Our hearts go out to Allen's family and the millions of former smokers who will be saddened by his passing," said John Dicey, Worldwide Director of Mr Carr's Easyway group. "He was an iconic figure and a real inspiration. His refreshingly different approach to stopping smoking earned him the position as the world's leading expert on helping smokers to quit."

Doctors were unable to say whether the disease was linked to his habit or his clients, who were allowed to continue smoking during their treatment. "I estimate I've cured 25 million smokers over the years," Mr Carr said in a recent interview. "And if my illness is the price for that, it's worth paying."

The former accountant claimed a 90 per cent success rate. He told smokers to focus on their addiction to nicotine rather than relying on willpower.

He said smokers were locked in a cycle of replacing the nicotine in their system. The pleasure they felt after each cigarette came from feeding the craving for nicotine. He further asserted that smoking was less addictive than is commonly assumed, that withdrawal symptoms are actually created by doubt in the mind of the former smoker, and that stopping smoking was not as traumatic as commonly assumed if that doubt can be circumvented. His contention was that fear of giving up was what causes people to continue smoking.

"I never wanted to be a smoker," Mr Carr said. "No one actually chose to become a smoker and there's not one smoker on the planet who wants their children to smoke. Basically, we are in it because we fall into a trap that we just don't know how to get out of."

When he read a medical book given to him by his son, he learnt that when nicotine leaves your body it creates an empty, insecure feeling. "When I was without cigarettes I got the panicky feeling, but when I lit up, the panicky feeling left so I was fooled into thinking that each cigarette was giving me some sort of crutch or benefit," he said. "Once I knew that it wasn't a weakness in me, which I'd believed before, I knew I would never smoke again."

Sir Anthony Hopkins described his method for giving up "not only easy but unbelievably enjoyable".

Mr Carr said he would have died 20 years ago if he had kept smoking. He smoked for more than 30 years, starting aged 18.

He also wrote a number of other "How To" books, on subjects such as losing weight and controlling alcohol consumption. He also wrote instructions on how to stop worrying, how to enjoy flying and how to be successful in business.

But he will be best remember for the book that started it all off; Allen Carr's Easy Way to Stop Smoking, sold more than seven million copies and has been widely praised by smokers who have used the self-help book to finally kick the nicotine habit.

He is survived by his wife, Joyce, four children, two stepchildren, 11 grandchildren, and a great-grandchild.