Spent yesterday afternoon filming in London.

I wasn't doing the actual filming - Dan Donovan and his sound engineer Ben were doing that - but I tried to make myself useful in other ways, buying lunch, hailing taxis, rounding up interviewees, asking the questions, that sort of thing.

Dan is making a short film to be shown at our Battle of the Brands event at the Churchill War Rooms next week.

The event is to mark the introduction of plain packaging in the UK from next Friday but not everyone we invited could make it so we decided instead to capture their thoughts on film.

Yesterday therefore we spent the afternoon running around London filming Mark Littlewood, director-general of the IEA; Claire Fox, director of the Institute of Ideas; Sam Bowman, director of the Adam Smith Institute; and Ella Whelan, deputy editor of Spiked.

Ella will be a new name to most of you but she's a rising star, increasingly on TV and radio talking about a variety of issues. (On Wednesday night she was in Belfast appearing on BBC Northern Ireland's Stephen Nolan Show.)

She impressed me enormously when I saw her on Nicky Campbell's Big Questions a few months ago. She's only 23 but she handles difficult issues really well.

A week or so ago she was interviewed about plain packaging on the Victoria Derbyshire Show on the BBC News Channel and impressed me again.

I found out she was a smoker when she posted a picture of herself on Twitter on No Smoking Day. Naturally she was smoking. Yesterday however she admitted she's almost given up but she doesn't strike me as the sort who will abandon her liberal principles so easily.

Ben, our sound man, has no plans to quit smoking. He's 22 and made the interesting point that people of his age have never known smoking in pubs and clubs yet lots of his friends smoke.

Neither the smoking ban nor the display ban has discouraged a new generation from smoking and plain packaging won't make any difference either.

Ben started smoking for the classic reasons. Without prompting he told me he began because of peer pressure and because both his parents smoked.

His father (who is 53 and therefore younger than me which made me feel extremely old) switched to e-cigarettes for a while but prefers smoking and has now switched back.

As readers know I'm all in favour of tobacco harm reduction as a goal and I support giving people the option of switching to e-cigarettes and other 'safer' products, but what I hate is the evangelical belief that all smokers would be better off switching and, wow, isn't vaping fun.

The reality, as I keep saying, is that a great many people enjoy smoking. Inform smokers about the alternatives but thereafter leave them alone and respect their choice.

Instead there's an assumption among some vaping advocates that if smokers can be persuaded (or forced) to switch to e-cigarettes their lives will never be the same again. Nirvana awaits.

The truth is that many smokers have tried e-cigarettes, found they don't like them, and keep smoking.

Claire Fox is another. Yesterday Claire told me she's keeping an open mind about vaping but when she previously tried to switch she didn't really like it.

There are a lot of smokers like that but their voices are never heard. The only people we hear from are ex-smoking advocates of vaping whose habit has become a hobby and, in some cases, an obsession.

Btw, Battle of the Brands is now fully subscribed. If you're coming on Tuesday I look forward to seeing you. It should be ... interesting.