Electronic cigarettes are to be classed as "medicines" under new plans to tighten up the regulation of nicotine-containing products.

Manufacturers will face tough tests before they can sell e-cigarettes as "licensed products", the Medicines and Healthcare products Regulatory Agency (MHRA) said.

The move will also mean licensed e-cigarettes can be prescribed by medics to help smokers cut down or quit.

It is estimated that 1.3 million people across the UK use battery-powered e-cigarettes, which can look like real cigarettes but users inhale a mist of nicotine instead of smoke. Some experts have said that if all smokers were to use e-cigarettes instead of normal cigarettes, millions of lives could be saved because, unlike real cigarettes, they do not contain harmful tar.

But others have raised concerns about safety and regulation of the products.

Now the MHRA will regulate the products so that there is a consistent standard across all licensed products sold over the counter.

It is not planning to recall unlicensed e-cigarettes but hopes that in the long term all products will be licensed.

"Reducing the harms of smoking is a key Government health priority," said MHRA group manager of vigilance and risk management of medicines, Jeremy Mean.

Deborah Arnott, chief executive of health charity Action on Smoking and Health, said: "Regulation will ensure that e-cigarettes meet the same standards for quality, safety and efficacy as medicines while remaining as readily available to smokers as they are today."