E-cigarettes cause less harm than smoking tobacco to users and bystanders, a major scientific review has concluded. Although the long-term health effects are unknown, current evidence does not justify regulating them more strictly than conventional cigarettes – or even as strictly. The review, carried out by researchers at Queen Mary University of London (QMUL), says health workers should support smokers who want to reduce their use of tobacco by switching to electronic cigarettes. Around 1.3million Britons use battery-powered e-cigarettes. The devices work by converting liquid nicotine into a mist, allowing users to inhale the drug while avoiding the harm caused by tobacco smoke. Professor Peter Hajek, of the UK Centre for Tobacco and Alcohol Studies at QMUL, said: ‘The evidence we currently have is clear: e-cigarettes should be allowed to compete against conventional cigarettes in the marketplace. Around 1.3m Britons use e-cigarettes The devices work by converting liquid nicotine into a mist, allowing users to inhale the drug while avoiding the harm caused by tobacco smoke. Some countries, including Norway, Singapore and Brazil, have banned them altogether. In Wales, health legislators are consulting on plans to make it the first part of the UK to ban e-cigarettes in enclosed public places. The UK’s drug watchdog has decided they must be regulated as medicines to make the products ‘safer and more effective’ but this won’t happen until 2016. E-cigarettes are thought to be healthier than normal smoking because they do not contain tobacco and other carcinogens found in cigarettes. But some experts have since expressed concerns about certain chemicals contained in the liquid, notably the compound propylene glycol. The scientific review, conducted by an international team of leading tobacco researchers and published in the journal Addiction, looked at 81 studies of e-cigarettes (EC) presenting original data that could guide regulatory decisions. It found the long-term health effects of e-cigarettes are not known. ‘However, based on the data available regarding the toxicant content of EC liquid and aerosols, long-term use of EC, compared to smoking, is likely to be much less, if at all, harmful to users or bystanders’ says the report. It also finds there is no evidence to back the claim by critics that e-cigarettes act as a ‘gateway’ to smoking in young people. In fact, there has been a drop in children becoming smokers at the same time that e-cigarette sales have grown, says the report. Yet many doctors want tighter regulations on e-cigarettes, according to a new poll from online network Doctors.net.uk. The poll, conducted among 525 primary care and hospital doctors, found that one in seven asked said e-cigarettes should be prescription-only – while one in six did not think e-cigarettes should be on the market at all.