A billion people will die from tobacco-related diseases such as cancer this century unless more are encouraged to quit, a UK expert warns. In the last century the death toll was about 100m. Professor Sir Richard Peto told a cancer conference in UK developing countries were likely to be hit hardest. Smoking currently kills about five million adults a year globally. Each year, about 30m people take up smoking around the world, Professor Peto said. He added: "If more than 20m of these continue to smoke and half are killed by their habit, then we are going to have more than 10m 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," warned the Oxford University Professor.