Hospitals should stock e-cigarettes for sale to patients and permit “vaping” in private rooms as part of the NHS ”smoke free” efforts, according to health chiefs.

The call comes from Public Health England, as part of an evidence update on the safety of tobacco alternatives which it says should be used more widely as quitting aids.

Meanwhile, Government officials should help manufacturers licence e-cigarettes as medical quitting aids.

Such a move would allow GPs to prescribe the devices to their patients who are trying to stop smoking.

In the independent review, which updates 2015 guidance, experts concluded that vaping only poses a small fraction of the risks of smoking and could be particularly helpful in mental health hospitals.

These patients are often on a long-term stay, and have high levels of smoking and tobacco related harm which could be mitigated by promoting vaping.

E-cigarettes could be contributing to 20,000 new quits each year, they estimated.

But the number of people using the products has “plateaued” and now stands at just under three million people in the UK, according to the review, which was conducted by experts from King’s College London and the UK Centre for Tobacco and Alcohol Studies, the University of Stirling and Cancer Research UK.