'Scientific evidence shows that there are benefits of exclusive use of e-cigarettes after using conventional cigarettes - particularly in areas such as respiratory diseases and cardiovascular diseases,' Riccardo Polosa, professor of internal medicine at the University of Catania, in Italy, told MPs.
'Our priority is to have as many smokers as possible switch to less harmful products.'
Peter Hajek, professor of clinical psychology at Queen Mary University in London, told the committee that, overall, studies have shown that the cancer risk of e-cigarettes is less than half the cancer risk of normal smoking.
'Nicotine is not a carcinogenic substance and there is no evidence that nicotine has a carcinogenic effect,' added Polosa.
'Combustion releases more [harmful] chemicals, e-cigarettes do not have combustion, so one has to assume that they are much safer than normal cigarettes,' agreed Lion Shahab, senior lecturer in health psychology at University College London.
In response to MPs' questions about the impact of e-cigarette use on non-smokers, Paul Aveyard, coordinating editor at the Cochrane Tobacco Addiction Group, explained that e-cigarettes are rarely a stepping stone from not smoking to smoking.
'The traffic is massively one way and rarely the other,' he said.
'E-cigarettes with nicotine are spectacularly unattractive to non-smokers,' agreed Hajek. 'It's the same thing with nicotine replacement therapies - it's extremely difficult to find a non-smoker who is addicted to them. If you take away the other elements of smoking it's not as attractive.'
'Phenomenal quitting aid'
Consistent with the experts' testimonies, Public Health England (PHE) said in 2015 that 'best estimates show e-cigarettes are 95% less harmful to your health than e-cigarettes'.
PHE recommends that smokers who have tried other methods of quitting without success be encouraged to try e-cigarettes as an alternative method of quitting.
In a session on cancer care in general practice at the RCGP annual conference in October 2017, Wandsworth GP Dr Alex Bobak, one of the first GPs to become a GPSI in smoking cessation, called e-cigarettes a 'phenomenal quitting aid'.
'We do not know the long-term risks - although they are likely to be minimal,' he said. 'But we do know short-term risks – which are minimal, and similar to NRT. Smokers want choice, and many want to use it - for goodness' sake let them'.
'It's a fantastic opportunity, but not being used right. It's not been given with support, and 40% use e-cigarettes alongside smoking. We should be clear that you use them with absolute cessation of combustible tobacco.'