The UK is being held up as a model for other countries because it shows how big health improvements can be made in just a few decades by cutting smoking.

BBC Asia Correspdondent James Miles reports

Between 1965 and 1995, annual cigarette sales in the UK have fallen from 150 billion to eight billion.

Tobacco-related deaths in middle-aged men (those aged between 35 and 69) have halved from 80,000 to 40,000.

There is likely to be a knock-on effect on deaths in old age.

However, worldwide cigarette consumption has remained constant over the last 20 years as statistics rise in other countries, including China.

Tobacco firms

As restrictions on smoking gather pace in the West, tobacco companies have been targeting their efforts on developing countries.

Four million people are expected to die from smoking in the year 2000 - about half from the West and half from developing countries.

But by 2050, 70% of deaths are likely to be in developing countries.

Only 30 years ago, however, Britain has the worst smoking death rates in the world.

The worst affected country in 2050 is likely to be China and the largest ever epidemiological research, published in this week's British Medical Journal, shows the extent of the problem.

The studies by researchers in China, the UK and the US, say that a third of all young Chinese men could die from smoking if significant efforts are not taken now to stop them getting hooked on tobacco.

The study says those who start smoking young suffer the worst effects.

Methodology

It is the first nationwide study of the effects of tobacco on a developing country and it will have huge implications for other developing countries.

Already its methodology is being copied in Russia, Poland, Cuba, Mexico, Egypt, India and South Africa.

This is because it is a relatively cheap way of analysing data.

It examines the deaths of about one million dead people, comparing smokers and non-smokers for causes of death.

"The traditional way of doing such a study is to take a large number of subjects and then wait for 20 to 30 years until they die, but that is very expensive," said Dr Zhengming Chen of Oxford University, who has overseen the research project.

Instead, the researchers just added some simple questions to the death certificate.

Families of people who died were asked if their relative was a smoker, how many cigarettes they smoked and when they started.

Dying like the rich

Professor Richard Peto of Oxford University said the research showed that "if the poor smoke like the rich they will die like the rich".

He said part of the problem in explaining the dangers of smoking was that it took many years for the effects of smoking to be felt.

He added that people always said they knew someone who had smoked and lived to old age, but statistics showed tobacco killed half of all smokers.