Britain is to regulate electronic cigarettes as non-prescription medicines from 2016 in an attempt to improve quality, though the country's drugs watchdog said they would still be sold in convenience stores.

Healthcare authorities around the world are grappling with how to deal with the battery-driven devices, which allow users to inhale nicotine-laced vapor and are increasingly popular as an apparently less harmful alternative to smoking.

A few countries have banned them outright - such as Brazil, Norway and Singapore - while others are opting for varying degrees of regulation, in some cases including limits on advertising and curbs on their use in public places.