Why people who have never smoked are getting hooked on vapes

When vaping first took off at Gracey Mungulu's school, she was vocal about the fact she found it as repulsive as smoking.

"I literally used to tell people like, 'Er, why are you doing that?'" she says.

But Gracey says the habit became so common among her classmates that by the age of 16 she too had taken it up, even though the first time left her coughing rather than inhaling.

"The more you see it, the more you start trying it a bit more," Gracey says, "and then eventually I just got used to it and I was just doing it all the time."

Now 21, she buys a refillable vape every day, using it whenever her hands aren't busy with her work as a hairdresser and in a school.

Gracey is among the more than one million people in the UK who say they have never smoked but now vape, according to recent Office for National Statistics (ONS) survey data – and that number has risen year-on-year.

When vaping first came to the market it was seen as a way to help smokers quit cigarettes.

Vaping nicotine, a highly addictive substance, is less harmful than cigarettes, but the long-term effects are not yet clear, according to the NHS.

So why are people like Gracey, who have never smoked a cigarette, taking it up?

The Londoner believes vaping helps when she's feeling socially anxious.

"It's the hand action," she says, "just having something in your hand, just having something in your mouth."

Like cigarettes Gracey's vape contains nicotine, a highly addictive substance that triggers withdrawal symptoms like irritability and anxiety when it leaves your system.

Vaping has become a "mindless action," she says. When she answers the call to talk to BBC News for this article, Gracey says that without thinking about it, she had been lying in bed, with her vape in one hand, and her other hand scrolling Instagram.

The habitual aspect of regular vaping is something GP Dr Helen Wall hears a lot from her patients.