It has been 50 years since a group of scientists in the UK issued the first health warnings about smoking cigarettes.

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.

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.

Al Jazeera's Emma Hayward reports from London.