The UK's leading medical cannabis expert is establishing a society to improve doctors' understanding of cannabis medicines, after it emerged that only two chronically ill children have been granted access to medical cannabis under an interim panel set up by the government, VICE can reveal.

The unwillingness of doctors and hospitals to recommend patients be treated with medical cannabis follows a letter by an influential doctors' organisation which suggested that "marijuana-related products" could cause brain damage.

Mike Barnes, the neurologist who supported six-year-old epileptic Alfie Dingley's successful application for medical cannabis, criticised the basis of the claim from the British Paediatric Neurology Association (BPNA), which represents doctors who care for children with difficult epilepsies in the UK.

"They have said that THC is dangerous to the developing brain, which I have to say is a complete misinterpretation," he said. "They are wrong to say that. The evidence that medical cannabis can be useful to treat pain, spasticity, nausea, vomiting, chemotherapy and epilepsy is pretty robust."

The BPNA's intervention came weeks after the government issued a license for a severely epileptic boy, Billy Caldwell, to be treated with cannabis oil, implicitly recognising the therapeutic value of cannabis medicines. The government later announced that cannabis-derived medicinal products will be legally prescribed to patients with "an exceptional clinical need", and introduced a panel to manage applications until a new wide-ranging system comes into place at some point during autumn.

However, many are unable to get the prerequisite support from healthcare professionals to make an application. Around 20,000 children in the UK have epileptic conditions that do not respond to conventional medicines, while tens of thousands more live with illnesses that could be treated with cannabis medicines.

A billboard telling Alfie Dingley's story. Photo: Amer Ghazzal / Alamy Live News

Currently, 15 families are in contact with End Our Pain, a leading campaign to legalise medical cannabis, after they were unable to get backing from their local NHS trusts or their doctor. Some families were able to make applications, but were rejected after five weeks of anxious waiting.

"When the government announced that an expert medical panel would be set up to consider urgent applications for permission to apply for a licence to use medicinal cannabis, it looked like a positive outcome for families like ours," says Ilmarie Braun, whose three-year-old son, Eddie, has a rare type of intractable epilepsy that cannabis oil provides relief from. "But the government failed to issue any guidance to NHS trusts across the country about the purpose of the panel, or the application process, so it fell to individual families to try to educate their doctors."

In order to be granted access to certain cannabis-based medicines, patients must demonstrate that "exceptional clinical need" in their own cases – a clause some doctors have understood to mean patients must prove that every single other anti-epileptic drug hasn't worked.

"Some doctors are interpreting the regulations to mean you must have tried all 21 anticonvulsant drugs before you can try cannabis, which isn't right at all," says Barnes.

An onus is also placed on families to prove that the prospective medicine is effective, meaning they must have previously gone abroad to legally buy and test it at their own expense – something which many either do not have the resources to do, or cannot do because they are too ill to travel.

Braun believes her son's application – one of the handful received by the panel – was refused on this basis, since the only licenses granted so far have been to those who have been able to leave the UK.

Others, such as Emma Matthews, would like to apply, but seemingly cannot since her family has not exhausted all other possible options. Her 15-year-old son, Louis, has a complex strain of epilepsy which is yet to be properly diagnosed, and his medical team are insisting he first tries every possible treatment, including a pacemaker-like generator.

"He's been given seven different anti-epileptic drugs, which have all caused terrible side effects and made his seizures worse," she tells me. "His energy levels are practically non-existent, and his cognition and memory have been significantly affected. Louis' specialists can't apply for a special license because they have to sign something which says all other conventional options have been tried. This means about five more medications and an implant which electrically stimulates nerves, a vagus nerve stimulator (VNS).

"Each new medication takes weeks to titrate and weeks to wean off, during which Louis will suffer rebound seizures, serious clusters and a severe form of seizure called status epilepticus, which needs emergency medical treatment. Last month he was in hospital twice, once with status epilepticus. The risks of sudden unexplained death in epilepsy and brain damage from these seizures is very high. Not allowing him the only medication that might help him just makes no sense."

Barnes recognises that doctors, many of whom understandably do not have any expertise in cannabis medicine, might be reluctant to recommend it. However, he is frustrated that some have chosen to ignore the emerging body of evidence – as well as a wealth of anecdotal reports.

"There is significant evidence that use of THC in the developing brain can cause damage to IQ, mental health and brain structure," the BPNA letter read. "These changes may be permanent," they concluded, despite recognising that cannabis oils may have anti-epileptic effects.

Barnes questioned whether the BPNA realised that instead of being high-THC and low-CBD, like much street cannabis, medical cannabis products usually include very small amounts of THC.

"There is some evidence that high-THC, low-CBD street cannabis does cause longer term cognitive damage among heavy recreational, mainly male, users starting in adolescence, however there are other studies that have refuted that," he explains. "CBD counteracts the effect of THC, so there is effectively no risk of these children getting cognitive damage from the tiny bit of THC we're suggesting. It's completely illogical to say, 'You can't have THC because it causes brain damage, but you can have this drug that causes brain damage, and you can continue to have seizures which also cause brain damage.'"

Barnes is to launch the British Medical Cannabis Society in November. It is developing the "Anslinger training programme", the only such scheme of its kind in the UK, which will be free to all doctors, and which he hopes will be accredited by the Royal College of GPs.

Anslinger was, according to Barnes, largely responsible for demonising cannabis in the early 1920s and 30s, so the name represents a thinly veiled barb towards him.

Hannah Deacon, mother of Alfie Dingley and spokesperson for End Our Pain, believes that the system should be much easier for people to access prescribed medical cannabis – a complaint that Barnes' new society seeks to redress.

"People are suffering enough without more hurdles in their way," she says. "This medicine could help so many and save the NHS so much money. I hope the government do the right thing and help patients to get far easier access and educate doctors urgently."

She explains that her son, Alfie, had clusters of seizures for years and was treated with IV steroids, which she says "can kill you, put you into organ failure or give you psychosis". After Alfie began using full extract cannabis oil he has been seizure-free, with his parents seeing a phenomenal improvement in his condition – one that has allowed him to return to school and live a relatively normal life.

Last week, the Labour MP Tonia Antoniazzi accused Home Secretary Sajid Javid of only paying "lip service to two high-profile cases", and urged Theresa May to "show real leadership". This followed a report on BuzzFeed that said the Home Office created a rapid response strategy to solve immigration cases that were generating bad publicity.