it doesn't involve inhaling tobacco smoke, and as the constituents of

smoke are the things that kill smokers, that has to be a good thing.

People die from the tar, the other constituents of smoke, but not the nicotine.

So the nicotine isn't the harmful component and electronic cigarettes allow smokers to get the nicotine

without all the other harmful stuff that comes along in cigarette smoke.

The first thing to note when considering the safety of e-cigarettes

is that the vast majority of e-cigarette users are people who are either still smoking,

and using them to cut down on the amount they smoke, or have used them to stop smoking.

If we try to put a figure on the relative risk of electronic cigarettes compared with smoking,

my view is that it's going to be well under 5 percent of the risk,

possibly slightly more for cardiovascular disease

but substantially less for chronic obstructive pulmonary disease and lung cancer.

When you look at the concentrations of and the nature of the toxins in cigarette smoke,

and then you compare that with e-cigarettes you see that really there's no comparison.

Most of the toxins in cigarette smoke aren't present at all in e-cigarette vapour

those that are present are in concentrations that are a hundred times less or more.

Some people say that the advent of electronic cigarettes is renormalising tobacco smoking –

so we see people using these devices, and it's making smoking more normal again.

Interestingly, we're just not seeing that in the data we have.

All that it does is normalise electronic cigarette use.

And if we could normalise electronic cigarette use for the nearly 9 million people in the United Kingdom

who are still addicted to tobacco, that could only be a good thing.

I think it's really important that people be reassured

that e-cigarettes, whatever you might see in the press,

are considerably safer than smoking,

and the evidence is pretty good that they can be effective in helping people to stop.