PHE, set up in 2013 under the last government's sweeping health reforms, is responsible for 'protecting the nation's health' and 'reducing health inequalities'.

At a press conference to launch its report last week, Professor Kevin Fenton, PHE's director of health and wellbeing, said it was vital the public is told e-cigarettes are safe.

A press release to accompany the launch said: 'The current best estimate is that e-cigarettes are around 95 per cent less harmful than smoking.'

When journalists asked where the findings came from, they were shown a chart showing cigarettes with a 99.6 per cent 'harm score', compared with 4 per cent for e-cigarettes.

The Lancet reveals that this claim - and the chart - originated from a study published in the journal European Addiction Research last year.

Three of the 11 authors of that study disclosed their role advising the e-cigarette industry in the original text of their paper.

The editors of the journal went even further, issuing the article with a warning of 'potential conflict of interest'.

But PHE did not repeat the declaration of interests anywhere in its 111-page review.

Even the industry-funded scientists were cautious about the robustness of their research, warning that there was a 'lack of hard evidence' for their claims. That caution did not make it into the PHE report.

E-cigarettes deliver a nicotine hit by heating liquids until they are vaporised, avoiding the tar and other carcinogens associated with breathing in smoke.

Around 2.6million adults in Britain have used e-cigarettes in the decade or so they have been on the market. Scientists generally agree they are far safer than tobacco, but concerns about long-term safety remain.

Last August, the World Health Organisation said e-cigarettes should be banned indoors over fears that they could harm non-users.

Last week's PHE report was greeted with glee by the £340million e-cigarette industry, and most public health experts and medical bodies also welcomed it.

But Dame Sally Davies, the Chief Medical Officer, said: 'People need to recognise they are not risk free, and they should only be used as a means to help smokers quit and stay quit.'

In an editorial, The Lancet says PHE has based a 'major conclusion' on an 'extraordinarily flimsy foundation' and 'has fallen short of its mission'.

The original 2014 study was led by Professor David Nutt, the controversial former government drugs adviser.

His team of 11 scientists included Italian addiction expert Riccardo Polosa, a consultant to e-cigarette distributor Arbi Group Srl, and to the pharmaceutical giants Pfizer and GSK.

Swedish scientist Karl Fagerstrom, another researcher, admitted to being a 'consultant for most companies with an interest in tobacco dependence products'.

And Jonathan Foulds, of Pennsylvania State University in the US, has links to several manufacturers of smoking cessation products, including Pfizer, GSK and Novartis.

Public Health England insisted last night it would stand by its claims, saying a previous 'expert review' had already endorsed the findings.

This is an article of The Daily Mail. Find the original version here.

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