A leading health professor has accused Public Health England (PHE) of ignoring mounting evidence on the harmful effects of e-cigarettes.

Martin McKee, professor of European Public Health at the London School of Hygiene and Tropical Medicine, said the UK was “out of step” with other parts of the world when it came to messages around the safety of vaping.

He said San Francisco had adopted a “sensible” policy in moving to ban e-cigarettes until their health effects are fully evaluated by the US government.

The US has also launched a drive to warn teenagers of the dangers of nicotine addiction from vaping.

Prof McKee’s comments were echoed by Dr Aaron Scott, from the University of Birmingham, who urged caution over e-cigarette use after his research showed they damaged lung tissue.

In an interview with the Press Association, Prof McKee said PHE “seems to be doing everything it can to promote e-cigarettes” and was choosing to ignore warnings over the risks.

He said: “The nicotine in e-cigarettes is not a harmless drug and then there all these other things such as flavourings that are inhaled.

“We haven’t had e-cigarettes for long enough to know the true effects.

“But when we look at the evidence we do have, there’s enough grounds for serious concerns.

“Given the short-term effects on lung function and cardiovascular effects, there is enough evidence to say we should be very, very careful.”

PHE has campaigned for cigarette smokers to switch to e-cigarettes, and has said they are 95% less harmful than tobacco smoking – a figure disputed by many health experts including Prof McKee.

He said PHE had failed to adequately show that e-cigarettes are an effective quitting aid and was ignoring evidence that they cause damage in their own right.

He said: “First of all, you’ve got to show that they’re safe. New products shouldn’t be introduced without showing that to be the case.

“It’s not whether e-cigarettes are safer than cigarettes, it’s whether they are actually safe.

“Then, if they are going to be demonstrated as a quitting aid, you’ve got to demonstrate that they are really a quitting aid and that they are at least as safe as or better than other products.

“But that has not been done. There is not the evidence at the population level that they are a useful quitting aid.”

He said PHE was turning a blind eye to increasing evidence that youngsters are trying vaping and are attracted to e-cigarette brands and marketing.

A report published by PHE in February said that regular use of e-cigarettes among young people remains low.

But its figures showed that the number of UK children and teenagers trying vaping has doubled in recent years.

Some 15.9% of children aged 11 to 18 reported having tried vaping, according to 2018 data, a rise from 8.1% in 2014.

The proportion who said they had never tried e-cigarettes fell from 91.5% in 2014 to 83.4% in 2018.

Prof McKee said there was “a worrying trend” of e-cigarettes clearly being made attractive to youngsters.

“It is now very clear these products are being pushed very hard to children,” he said.

“This creates an entirely avoidable risk of a new generation that will be addicted to nicotine.”

He warned that youngsters could become hooked on Juul, an e-cigarette that has been blamed in the US for creating nicotine addiction in children, and which was introduced to the UK market last summer.

“Why would British children be any different to American children in that respect?,” he said.

Prok McKee also called for tighter regulation of the whole e-cigarette market.

“I think e-cigarettes should be regulated as medicines which means you’ve got to demonstrate that they are safe and effective,” he said. “It’s as simple as that.”

And he attacked voluntary codes of conduct adopted by the e-cigarette industry, adding: “Nobody in public health should take voluntary codes of conduct at all seriously.

“There’s loads of research showing that voluntary agreements don’t work.”

He continued: “Tobacco firms are doing a lot of brand stretching here. They are promoting products that look very much like cigarettes with similar colours, logos and names.

“The firms are trying to become socially acceptable. They have been internation pariahs and now they’re trying to present themselves as part of the solution.”

Prof McKee said the position held by PHE was “untenable in the long run”.

He said: “We are hugely out of step with the rest of world.

“I think a small group of individuals in England have been able to devote a lot of effort to take forward the agenda here.”

Dr Aaron Scott, from the University of Birmingham’s Institute of Inflammation and Ageing, has published a paper in the journal Thorax, funded by the British Lung Foundation, showing that vaporised e-liquid fluid has a similar effect on the lungs and body as seen in regular cigarette smokers.

He told the Press Association: “We don’t know what the long-term data is but we have shown that it’s cytotoxic and it’s pro-inflammatory, just like cigarette smoke is over the short-term.”

He said it was difficult to get funding for long-term studies “because PHE want to push the message that they (e-cigarettes) are not harmful”.

He said long-term studies were needed so people could make their own decision “based on national data rather than this 95% supposition”.

He added: “We only have evidence for short-term and in the short-term it’s definitely harmful.”

Dr Scott said it was understandable that PHE wanted to “put out its strongest message possible” that e-cigarettes are less harmful than smoking.

But he added: “I think we should be more cautious. They’ve advocated for less regulation of e-cigarettes to make it easier for people to take up these devices and I don’t agree with that.”

He added: “You can go into a pound store anywhere in the country and buy e-cigarette liquid for £1.

“You can do that with very little regulation, so it’s very easy for example for kids to get that, it’s very accessible.”

Professor John Newton, director of health improvement at PHE, said:  “While research on e-cigarettes continues to emerge we must act on what the current evidence tells us.

“There is widespread academic and clinical consensus that while not without risk, vaping is far less harmful than smoking.

“This view is held by many across the world, including the Royal College of Physicians, Cancer Research UK, the British Medical Association and the National Academy of Sciences in the US.

“There is no situation where it would be better for your health to continue smoking rather than switching completely to vaping.”

Prof Newton said PHE was “alert to the risks” and the UK had taken a “careful approach to maximise the opportunities that e-cigarettes present to help more smokers quit.”

He added: “The UK has some of the world’s strictest e-cigarette regulations including advertising restrictions, minimum age of sale and maximum nicotine content.

“Approaches similar to ours have been adopted by Canada and New Zealand, both of whom had previously banned e-cigarettes.

“There is strong evidence that vaping is highly effective in helping smokers quit.

“Regular e-cigarette use among young people remains low and almost entirely confined to those who smoke or have quit, while smoking rates continue to fall.

“The current evidence does not support the concern that e-cigarettes are a route into smoking among young people.”