The British government's Science and Technology Committee has launched an inquiry into the impact of e-cigarettes on health, along with regulations guiding their use, and the financial implications on business and the NHS.
Committee chairman Norman Lamb MP said that almost three million people in the UK now use e-cigarettes (vaporisers) but claimed "there are still significant gaps in the research guiding their regulation and sale."
He said: "They are seen by some as valuable tools that will reduce the number of people smoking 'conventional' cigarettes, and seen by others as 're-normalising' smoking for the younger generation.
"We want to understand where the gaps are in the evidence base, the impact of the regulations, and the implications of this growing industry on NHS costs and the UK's public finances."
On the subject of regulation, the committee is also looking for evidence on the implications of Brexit.
The EU's Tobacco and Related Products Regulations 2016 (TRPR) monitors tobacco substitutes like e-cigarettes as if they were tobacco products.
That led the UK's advertising watchdog to recently conclude that generic lifestyle campaigns urging people to improve their health by vaping instead of smoking may fall foul of EU law.
However, in July the Department of Health said in an official outline: "Evidence is increasingly clear that e-cigarettes are significantly less harmful to health than smoking tobacco."
The Department of Health continues to monitor the impact of e-cigarette regulations, while Public Health England provides evidence-based guidance on what is known, and unknown, about the risks of e-cigarettes relative to smoking.
Adult smokers in the UK last year numbered 7.6 million (15.8 per cent of the population). The use of e-cigarettes has risen to an estimated 2.9 million adults, compared to 700,000 in 2012.
The committee is asking for written submissions of evidence by December 8. ®