'I was addicted to smoking Spice vapes at school'

"I didn't care how expensive it was, I didn't care if I had any money left - I just wanted to buy it."

Rather than doing school work or spending time with friends, all 14-year-old Ben, whose name we have changed, could think about was trying to get hold of the drug Spice.

"I became dependent on it and I felt like a drug addict, I realised I was doing it to feel normal and regulated," he tells the BBC.

He says he first tried a Spice vape while at a friend's house, believing it contained THC - the main psychoactive ingredient in cannabis.

Vapes stashed in old teddy bears

What was actually in the vape was a synthetic cannabinoid, a lab-made drug intended to mimic the effects of cannabis.

"After using it [Spice] for a while, I realised the effects of real THC would be different," says Ben.

"I don't know why I didn't realise this sooner but the colour was very artificial - bright blue or red - obviously that's not from a plant."

His testimony comes as a new report finds one in six vapes tested across 38 schools in England contain Spice.

The drug can be more harmful and unpredictable than cannabis and can cause dizziness, breathing problems, heart palpitations, psychosis and seizures.

Ben, who is now 16, says he was lucky not to have any immediate adverse reaction, although very little is known about the long-term effects of Spice use, particularly in children.

"I found myself doing it every second of the day," he says.

"I'd be like 'oh, you're not as high as you were 10 minutes ago', so I'd have another bit."

He says he used his vape everywhere, including in classrooms at school.

It is illegal to sell vapes to anyone under the age of 18 in the UK, while vapes containing spice or THC are banned entirely

Spice is cheaper to produce than cannabis but has much more potent effects and many people purchasing Spice vapes believe they are getting genuine THC.

Ben's mum Katie, whose name we have also changed, says she found out he was using Spice vapes from his friends' parents.

"They [his friends] managed to stop because they knew it was bad but he couldn't," she says.

"He used to hide them in the gutter above his bedroom window and in the toilet cistern - I'd cut open his old teddy bears and he'd stashed them in there - my husband and I didn't know what to do."

'Vicious cycle'

Spice and THC vapes are illegal in the UK and cannot be purchased in corner shops and supermarkets like nicotine vapes.

It is also illegal to sell a vape or any nicotine product to someone under the age of 18.

Ben says he got his from a dealer he found on social media, meeting them at a nearby train station.

"Without it [Spice], everything would feel really dull, I'd feel demotivated," he says.

"I knew it was bad for me but I was in a vicious cycle of needing to get more and as soon as I had finished one I'd get another one - even when I'd get one confiscated, I'd immediately be set on getting another one."

He says what began as "communal activity" became "very solitary" once he was addicted.

Prof Chris Pudney, from the University of Bath, has conducted an investigation on the use of Spice vapes in schools, using a portable device that can instantly detect synthetic drugs.

He and his team collected confiscated vapes from 38 schools across England, including London, the West Midlands, Greater Manchester and South Yorkshire.

He found that out of nearly 600 confiscated vapes, one in six contained Spice and one in 100 contained THC.

"Our research into understanding Spice vapes started in prisons, where usage is endemic and causes a great deal of harm - nearly half of all non-natural deaths in prisons are associated with Spice," Prof Pudney says.

The number of children collapsing in schools after using Spice vapes is "so high", he says, adding that it is hard to find a school "where a child hasn't collapsed" from suspected Spice use.

'Spice is a gateway drug'

Prof Pudney says he has also heard of children spending time in intensive care after going into cardiac arrest and is "worried about the summer" when children are not in school.

He says: "If a child uses one on their own in their bedroom and has a cardiac arrest, they don't have the people around them, like in schools, where effective CPR can be provided and an ambulance can be called.

"That's where the risk really lies - you can self-regulate nicotine consumption but, with Spice, it's so potent that you can use a relatively small amount and have a serious outcome."

What are the effects of taking Spice?

• Dizziness and confusion

• Mood swings

• Anxiety and paranoia

• Suicidal thoughts

• Memory problems and amnesia

• Nausea and vomiting

• Hot flushes

• Increased heart rate and blood pressure, which may cause chest pains and damage your heart and even cause a heart attack

• Tremors, seizures and fits

Source: Talk to Frank

If you have been affected by any of the content in this story you can contact BBC Action Line for help.

Prof Chris Pudney (left) upgrading Devon and Cornwall's drug detection device

The professor has been creating technology that can instantly detect substances found in vapes.

He has been working with Devon and Cornwall Police, who are trialling one of his devices to help understand the scale of Spice use in the local area.

Work is being overseen by their drugs liaison officer Det Con Nick Burnett, who calls Spice a "gateway drug".

He says he worries about children getting into debt with drug dealers and being caught up in crime.

"Continued use of Spice affects everybody differently, it can lead to unconsciousness, which can leave you in a very vulnerable position," says the officer.

Det Con Burnett says violence against women and girls is on the increase in the area and worries about the potential for blackmail, using videos of children on the drug or even physical or sexual assault.

Most synthetic cannabinoids are categorised as Class B drugs, which means they are illegal to have for yourself, give away or sell.

After being grounded by his mum and having no money, access to a phone or ability to leave home, Ben says it "clicked" that he did not need the drug.

He says he used it for just under a year, spending hundreds of pounds on it.

"I felt really empty, like a shell of myself," he says of withdrawal.

"I didn't do it for two, three weeks - your body readjusts and I didn't feel the urge to do it any more, it was kind of like my life was back to normal," he adds.

Harm reduction charity Cranstoun says the best way to stay safe is by not using vapes at all but says if someone does buy a new batch or type of THC vape, they should inhale once and gently, to assess its effects.

It also recommends a vape is consumed around others and that an ambulance should be called immediately if you or another user of the vape become concerned.