An Oxford University researcher predicts a billion people will die from tobacco-related diseases such as cancer during this century.

Professor Sir Richard Peto says smoking currently kills about five million adults a year globally.

He says each year, about 30 million people start smoking around the world.

Peto adds, "If more than 20 million of these continue to smoke and half are killed by their habit, then we are going to have more than 10 million tobacco-related deaths a year. So in the present century, if we keep on smoking the way we are we will have about 1,000 million deaths."