Figures from NHS England show there were 15 cases where children aged nine or under needed to be admitted in the year to April, up from 12 last year and two the year before that.

Professor Andy Bush, a paediatric chest physician at the Royal Brompton Hospital in west London, says he's "absolutely horrified" by the statistics.

"Young children are being exposed to substances of addiction, substances that are toxic and some of the toxicity is not known," he said.

"It's a jungle… we just do not know what is in most of these things.

"If a teenager starts smoking cigarettes, probably the worst that's going to happen to them is they're going to be sick and throw up behind the bike shed.

"The acute use of e-cigarettes can put them in hospital, can put them in intensive care, things like lung bleeding, lung collapse and air leak, the lungs filling up with fat."

For many smokers, vaping has been the key to quitting what is the biggest preventable cause of death.

But Rachel Howe is convinced it's what killed her 18-year-old daughter, Rosey Christoffersen in February 2015, six months after she began vaping heavily.

"She was supposed to call me at 5.30pm but she didn't call," she said.

"I rang her phone and one of the ambulance crew answered and said we're with your daughter, we're working on her. She'd come out of work and collapsed."

Rosey had suffered a heart attack, but what had caused it was the sudden collapse of both her lungs - a bilateral pneumothorax.

Her brain was starved of oxygen and two days later it was made clear she would not survive.

Rachel, from the Wirral, was told Rosey's lungs were "just a mass of holes and blisters called blebs".

"To be honest, there was just a lot of stunned silence at the hospital," she said.

Rosey had been to the doctors a number of times with chest pain in the months before her death but as a fit and active footballer it was put down to a pulled muscle.

"I was finding bottles and bottles of the empty liquid," said Rachel.

"She constantly had it in her mouth. And I kept saying to her, you know, you wouldn't smoke that much... why are you vaping that much?"

No post-mortem was carried out, no official link was made, but Rachel says doctors told her vaping was "probably" to blame.

Professor Bush goes further than that, adding he has never seen double lung collapse in a fit, young person.

"I think that mother is right," he said.

"I cannot think of any other explanation that would cover the facts."

It's illegal to sell vapes to under-18s and the boxes are clearly labelled.

But it's easy to see why certain products would appeal to children.

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They're brightly coloured, flavoured like fruit or sweets, and at around £5 each for a disposable vape, cheap.

Some look like make-up, others like pens.

The government recently announced it would be clamping down on rogue firms unlawfully targeting teens with advertising on platforms like TikTok.

"Illicit vape enforcement squads" are also being set up at a cost of £3m to uncover the traders selling to young people.

In total, 40 young people aged up to 19 were admitted to hospital in the past year from vaping.

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But John Dunne, from the UK Vaping Industry Association, says "the statistics would not exist if children were not getting their hands on vapes".

"Every year according to the NHS some 76,000 people die from smoking, whereas there has not been one officially confirmed report of a death from vaping even though the category has been available in the UK for around the last 15 years," he said.

"The fundamental issue that needs urgently addressing is the woeful level of enforcement of vaping age regulations across the UK.

"Whilst we see recent measures announced by the government as a step in the right direction to tackle youth vaping… much more needs to be done to support Trading Standards in their efforts to tackle rogue traders and cut off the source of supply of vapes to minors."

He wants on-the-spot fines of £10,000 to be introduced for those caught selling to young people.

Rosey was due to start a new job as a trainee hairdresser a couple of days after collapsing.

Instead that day she was being kept alive so her organs could be donated, helping eight other people.

Rachel wants more research to be done into the impact vaping has on young people.

She's made it her mission to tell her daughter's story to any young people she sees vaping, or who come into the shop she works in asking for them.

The impact on young lungs is only just emerging, but she knows there's too much at stake to ignore the risks.