Michael Bloomberg and Bill Gates, the US billionaires, have rallied together to launch a global anti-smoking campaign, committing a combined $500m to help governments in developing countries increase tobacco control.

Gates, who is the third richest person in the world with a fortune of $58bn, and Bloomberg, who comes in 65th on the Forbes Rich List with $11.5bn, are pooling their capital and contacts to urge governments to implement proven interventions to combat tobacco use.