Table 3.

Categories of the COM-B model and examples of narratives from participants.

Themes	Physical Capability	Psychological Capability	Physical Opportunity	Social Opportunity	Automatic Motivation	Reflective Motivation
Narratives	“it was hard to tell if, you know, you wanted the equivalent of one cigarette’s worth of nicotine, (yeah) it was hard to gauge how much of that you had to take in, so I wasn’t sure if it was more concentrated or not. Obviously, you can easily inhale, you know, and I think you usually get like a flash of light on the end.” (Yusef, current smoker and ex-vaper, aged 18–24 years).	“I almost use the e-cigarette to relieve myself from the dirt I’m putting into my system, to give myself a break, almost. So that way I’m still getting my nicotine… The problem with cigarettes, obviously, is that you see it’s not only the nicotine, it’s the other stuff and I’m very aware of that.” (Fraser, current smoker and ex-vaper, aged 35–49 years).	“He (shop assistant) was just, “Have you smoked or do you smoke?” and I was like, “Yeah”and (he) was like, ”Try this”. He didn’t have to do much. I was curious about the product.” (Ethan, current smoker and current vaper, aged 18–24).	“I think it was my friend (who) encouraged it… She went and got it for me. She said, “I’ll go to the shop and get you one, give me the money”, and then she went and got it. She encouraged me…” (Holly, current smoker and current vaper, aged 25–34 years).	“I remember thinking it was a fad, like the herbal cigarettes my Mum used to smoke. I just remember thinking they were silly, so I never really thought anything of it, and then I tried them and realised it was actually quite effective.” (Grace, ex-smoker and ex-vaper, aged 25–34).	“If I’m gonna be an addict to an e-cigarette, it’s gotta be better. I mean, if all I’m gonna go do is swap my addiction over to an e-cigarette then, I think it’s worth doing.” (Holly, current smoker and current vaper, aged 25–34 years).
		“One of the biggest negatives is the sort of constant, um, uneducated debate about it… even almost to the point of… I don’t actually know anything about them. I just use them and then you get, like, there’s a newspaper article or something (reporting that) these things are killing our kids.” (Connor, ex-smoker and current vaper, aged 18–24 years).	“The local pound shop started selling like, er, disposable e-cigarettes with the promise that buying one was equivalent to like a pack of twenty. So £1 versus £6, £7, £8. So you know, it seemed like a good deal.” (Yusef, current smoker and ex-vaper, aged 18–24).	“When they tried those e-cigarettes a year or so ago, a mate goes to me, “It works”. So I was like, “I have to give it a try”. Then my brother, as well, my brother smokes, or used to smoke as well and he’s the one that got me on e-cigarettes as well recently.” (Liam, ex-smoker, ex-vaper, 25–34).	“I love the smell of cigarettes. I love the way they taste, the disgusting taste that’s perfect, the smoke that burns. That’s something that I really enjoy... My boyfriend tried to convince me (to try an e-cigarette)… and I said… “I don’t want to do it. Just leave me alone so I can smoke my cigarettes”.” (Una, ex-smoker and current vaper, aged 25–34 years).	“Just chewing gum or putting a patch on, it’s not the same. You need to have your cigarette, like light up and everything… So… it’s either you have your normal cigarettes and like cut down or go for the e-cigarette. So obviously I decided to go for the e-cigarette.” (Belle, ex-smoker and ex-vaper, aged 18–24 years).