Media playback is unsupported on your device Media caption Cannabis oil: 'Why I break the law for my son'

Scared her son could die from violent seizures, a mother began breaking the law in an attempt to protect him.

After seeing severe epilepsy stop his breathing and leave him unresponsive, Sophie said any parent would "take the risk" and turn to cannabis oil.

She is one of a "silent majority" buying the drug online and said it had stopped his up to four seizures a day.

A consultant who prescribes it in Wales called demand a "phenomenon" but warned many were ignoring the serious risks.

"There is the risk of actually being caught purchasing the product, because it's illegal," said Sophie, which is not her real name because she fears prosecution.

"The desperation you feel as a parent to protect your child is ingrained and inbuilt, so when you see your child having a seizure where they're not breathing and not responding, when you don't know if they're going to survive this one, then I think any parent would take that risk."

Image caption For two years, Sophie has been buying illegal forms of high-strength cannabidiol (CBD) oil for her son

On the surface, Sophie's life as a mum and working professional in south Wales does not appear out of the ordinary.

But she is keeping a closely guarded secret.

For two years, she has been buying illegal forms of high-strength cannabidiol (CBD) oil - which is made from cannabis.

Sophie cares for her son, 22, who has a rare and severe form of epilepsy, which means he could die each time he has a seizure.

"Being part of the epileptic community, everyone talks," she said.

"We were seeing that lots of people were starting to try it and said it had very positive results. It swept through the community very quickly.

"We turned to cannabis oil probably two years ago now. Since he's started taking it the effects have been really quite dramatic, the seizures have slowed right down.

"He rarely gets a seizure now whereas he would be having maybe one, two, three, four a day, quite easily, that was a regular occurrence."

Sophie orders bottles of cannabis oil from a so-called "grey market" of suppliers on the internet.

Image copyright Getty Images Image caption People have read testimonies online from US states where cannabis-derived medication is allowed

She said many of the sellers she has dealt with were families similarly affected by epilepsy, who had taken to growing cannabis at home.

Paediatric neurologist Dr Gareth Thomas is one of three consultants in Wales who can legally prescribe cannabis oil to young epilepsy patients in special cases.

He said demand had become a medical "phenomenon" the likes of which he had not seen in 25 years.

"Over the last six to eight months we've had to deal with the fact patients are sourcing CBD oil from overseas, from elsewhere in the UK and from non-NHS sources," he said.

"It's come to the point now that it's discussed in the majority of epilepsy consultations that I see.

"In many cases, while they might have heard of the potential therapeutic benefits, they haven't considered the other things that we think about - like the effect it could have on other medications."

Media playback is unsupported on your device Media caption Cannabis-derived medicines: What you need to know

Dr Thomas encourages patients to be honest with him if they use it so he can list it in their medical notes, but warns historic scandals, such as Thalidomide, should be seen as a warning about what can happen when new drugs are not properly tested.

While demand for medical cannabis among epilepsy patients may be linked to a rule change by the Home Office last year, which allowed it to be prescribed to some children with rare forms of the condition, others are experimenting with it for pain relief.

Mike, not his real name, said he started sourcing CBD oil online for his wife - who lives with chronic back pain - after reading social media comments and watching documentaries online.

"The condition that my wife suffers from is a bone-on-bone pain which is constant every time that she moves, every time she gets up or sits down," he said.

"She's in constant pain 24/7 and we do anything we can to help with that, or alleviate that just to give her a quality of life.

"The positives we've found have been both for the physical pain that my wife is in, and also for the mental health anxiety issues that she has."

Miracle cure?

But some campaigners argue people are reading unchecked claims about apparent benefits online.

"Social media definitely has an influence, especially social media influencers in US where it's legalised, but not enough research has gone in to it," said epilepsy awareness campaigner Torie Robinson.

"I find it frustrating that people are allowed to have these misconceptions about how it should be treated.

"In my experience normal drugs don't always cut it so people find themselves wanting a miracle cure, particularly if it appears to be natural."

Media playback is unsupported on your device Media caption Bogarts CBD Coffee House in Swansea sells coffee containing CBD

A Welsh Government spokesman said: "Unlicensed cannabis-based products should only be used for medicinal purposes under the close supervision of specialist doctors.

"The use of some cannabis-based products without medical supervision may be associated with significant risks to health without offering any medical benefit.

"This is why arrangements are in place for the prescribing of cannabis by specialist doctors."