It has been 50 years since a group of scientists in the UK issued the first health warnings about smoking cigarettes.<br /><br />In the past decade there have been bans or partial bans on smoking in public in some countries, as well as a worldwide wave of health campaigns against tobacco.<br /><br />But smoking still kills at least six million every year, according to the World Health Organisation, while about one billion people across the world continue to smoke despite the risks.<br /><br />Al Jazeera's Emma Hayward reports from London.
