Like most teenagers, Lucy Stafford has plans. Normal plans. The plans anyone makes as they progress into adulthood. She wants to complete her degree, spend time with friends and family, and explore her independence.

But, unlike most teenagers, the 19-year-old from Cambridge has a rare and debilitating medical condition – Ehlers Danlos syndrome – that affects her connective tissue, causing her limbs to dislocate and muscles to spasm. When the Observer interviewed her last week she had dislocated her shoulder that morning, a common occurrence.

And yet she was disarmingly, joyously upbeat.

The reason? She is one of the very few people in the UK to have been issued with a private prescription for medical cannabis since the drug was legalised a year ago last Friday, something that she and her doctor claim has transformed her life.

Having suffered lengthy bouts of chronic pain since she was 10, Stafford has spent most of her teenage years on strong opiates, most recently fentanyl, the synthetic analgesic 50 times more potent than heroin.

Down the years, she has had numerous operations and treatments for lower-back pain, including steroid injections, and has been prescribed courses of the powerful painkiller tramadol, to which she became physically dependent. Her vomiting was so severe she was admitted to hospital for intravenous rehydration. She has endured multiple sepsis and urinary tract infections and for much of her life has needed a catheter. Long stays in hospital have been common.

“Coming off fentanyl was the best thing that ever happened to me,” said Stafford, who since she started taking medical cannabis has begun studying with the Open University. “This prescription saved my life.”

She talked about dislocating her shoulder as if she had stubbed her toe.

“Before cannabis I would have had to take a large amount of opiates. I would have been … crying in pain for most of it, whereas now I am able to function. Sure I need to rest and take it easy but it has made living with my condition manageable and lets me function and have a life, something I never expected to have.”

It was when attempts to surgically fix her constantly dislocating jaw failed, causing it to go into spasm for two months, that Stafford’s NHS pain-management specialist tried to prescribe her the cannabis-based medicine Sativex, normally used to treat people with multiple sclerosis.

“It was an act of desperation, they couldn’t increase my fentanyl any more,” Stafford said.

Her local NHS Trust refused to pay for the medicine, so she tried self-medicating with illegal cannabis. Worried about being arrested, she paid for a private consultation and is currently one of only about 100 people in the UK to have a private prescription for medical cannabis.

Experimenting with different strains of cannabis, oils and vapes has produced life-changing results.

When her joints dislocate, Stafford claims that vaporising cannabis reduces her pain levels from a 10 to four within minutes. And she sleeps. Properly. For the first time in years.

Pruning a marijuana plant at a facility in Uruguay, which will be harvested for cannabis oil. Photograph: Matilde Campodonico/AP

“Chronic pain means you don’t sleep, you can’t meet friends, be with your family, you can’t think, you don’t have your brain and then when you add in opiates you become zombified. A year ago I was a very, very different person. On my medical notes my doctor described me as having transformed. After so many years of being on opiates and in uncontrollable pain, I accepted that I was going to be in so much pain for ever. I had lost so much of myself. I had no ambition for what I would do. All I did was exist.”

She speaks with almost childish wonder at the change in her fortunes.

“I feel like I’ve become myself for the first time in my life. It’s absolutely unbelievable. I’m at university, I’m living my life, I’m seeing friends and just doing all the things that I hoped I would do. If you had told me my life would have been like this a year ago I would have laughed.”

But a huge problem looms on the horizon: Stafford’s new life is financially unsustainable. She paid £250 for a private pain consultant to write her the prescription for medical cannabis, a significant sum for a student. But this is nothing compared with the £1,500 a month she was initially paying for her various cannabis products.

Since then the price she pays for her medicines and oils has come down to £800 a month but it is still a huge amount to find.

She is outraged at having to pay so much money for something that she believes should be provided on the NHS.

“The law changed a year ago and you would expect some patients would by now have access [to medicinal cannabis on the NHS] but literally nobody has, unless they are willing to go into debt for it. It’s disgusting.”

When the law was changed 12 months ago, scientists, researchers and campaigners hailed it as a “landmark victory”. The then home secretary, Sajid Javid, said: “We have now delivered on our promises … we will work with the NHS to help support specialists in making the right prescribing decisions.”

Future generations will look back in disbelief at our callousness Baroness Meacher, campaigner

But, in Stafford’s summation: “Our hopes have been dashed, nothing has happened.”

Department of Health figures confirm that in the first eight months since medical cannabis was legalised, just 12 prescriptions were issued for unlicensed cannabis medicines –those other than Sativex, or Nabilone, which is given to patients undergoing chemotherapy, both of which have been subject to randomised control trials.

“The people who benefit the most from the new regulations are those who can afford private healthcare,” said Alexandra Curley, head of insights at Prohibition Partners, a consultancy set up to “advance the global cannabis industry”. “Restrictions and lack of availability is creating a two-tier system of access for patients.”

The alternative is to buy illicit cannabis. A cottage industry has sprung up among growers producing not-for-profit medicine-grade cannabis to help treat themselves and others with health problems.

“Severely disabled patients who rely on their medical cannabis live in daily fear of arrest for growing their own medicine,” said Baroness Meacher, chair of the all-party parliamentary group for drug policy reform. “Is it right for patients to be criminalised for looking after their health and saving the NHS huge sums? Future generations will look back in disbelief at our callousness.”

The claim that medical cannabis will save the NHS a fortune is beguiling. Stafford estimates she was costing the NHS £150 a day on specialist nutrition, £1,000 a month on medication, £188 a month on catheters, and this is before hospital admissions and nursing costs are factored in.

But most NHS doctors are still reluctant to write prescriptions for medical cannabis. Many are wary of the hyperbolic claims being made for it.

“The law was changed but there’s been no education, no trials,” Stafford said. “Doctors have been taught for decades that cannabis is a dangerous recreational drug. There’s been no effort to try to increase understanding of medical cannabis – it’s been completely lost.”

In August the National Institute for Health and Care Excellence (Nice) published an interim review that said medical cannabis should not be prescribed for a range of conditions including chronic pain.

Pre-rolled marijuana joints on sale at the Medicinal Cannabis Dispensary in Vancouver, Canada. Photograph: Elaine Thompson/AP

Nice said there was a need for more research into the use of cannabis-based medical products (CBMP). It said “current research is limited and of low quality”, and added that clinical trials had shown a high level of adverse responses.

“There is a clear need for more evidence to support prescribing and funding decisions, and we are working hard with the health system, industry and researchers to improve the knowledge base,” a Department of Health spokesman said.

Now, in an attempt to break the deadlock, a group of scientists – backed by the Royal College of Psychiatrists – will this Thursday announce that they are to conduct Europe’s largest study into the effects of medical cannabis. About 20,000 patients will receive heavily subsidised products to help treat a range of disorders including epilepsy, chronic pain, multiple sclerosis, post traumatic stress disorder and other chronic conditions.

That the UK currently lacks this knowledge base seems perverse: it is the largest producer of medical cannabis in the world. According to the United Nations International Narcotics Control Board, in 2016 the UK produced 44% of global cannabis plants intended for medicine and scientific research. Much of this is exported to other countries who turn it into medicinal products, which the UK subjects to hefty import restrictions.

Those firms wanting to bring products into the UK must apply to the Home Office for a licence. Under the current system, it takes eight to 10 weeks for a product to be made available to patients after they have been issued with a prescription, with the result that the prescriptions often expire before the drug can be sourced.

Tellingly, the first shipment of medical cannabis did not arrive – from the Netherlands – until February 2019, four months after it was legalised.

Campaigners claim the time lag limits the supply of medicinal cannabis into the UK, forcing patients into taking a break in their medication. This is a problem: smooth supply is critical during the titration phase of taking a medicinal cannabis product – when the concentration a patient requires is established.

Unsurprisingly, the CBMP industry is not beating a path to the UK’s door: the market is just too small, too inaccessible compared to other European countries such as Germany where 142,000 prescriptions were issued in 2018. Companies such as Cannamedical, which profitably sells medicinal cannabis to pharmacies in Germany for €10 (£8.60) a gram, must sell it for £30 a gram in the UK to achieve a similar profit margin.

“The system isn’t working and is failing patients who need it,” said Marc Davis, an investor and expert on the cannabis market. “This vicious cycle not only puts patients at risk but also spurs crime and impacts the economy in terms of lost tax revenue.”

Currently Stafford can obtain products made by only one company in the Netherlands. She is waiting on an order for products from Canada to be approved.

“There are lots of different flowers and oils out there,” she said. “Patients need access to a wide variety, but at the moment, due to all the restrictions on importing, it makes it so expensive and offers such limited choice.”

There are signs things are changing, albeit slowly. In the summer Ignite, the company founded by the social media celebrity Dan Bilzerian, known for hosting parties with scantily clad models, launched the UK’s first major campaign promoting cannabidiol, better known as CBD, the non-psychoactive component of cannabis which, it is claimed, improves mood and concentration.

Cannabis entrepreneur and social media celebrity Dan Bilzerian. Photograph: Rex

But there remains a sense that the UK is lagging behind.

“Almost a year ago hopes were high after the law was changed, and yet implementation has been characterised by dither and delay,” said Tonia Antoniazzi MP, co-chair of the all- party parliamentary group on medical cannabis under prescription.

The law change followed several high-profile cases involving young children, notably eight-year-old Alfie Dingley, whose mother claimed medicinal cannabis helped combat his severe epilepsy.

But in September, 10 families marched on Downing Street protesting that not one of them had received an NHS prescription for such medicines despite promises to the contrary from health secretary Matt Hancock.

“It has been a frustrating year for families like ours,” said Dingley’s mother, Hannah Deacon. “Even after our high-profile case, my son still can’t access all of the medicinal cannabis products that would truly help his intractable epilepsy. That situation needs to change. For us and for thousands of others whose cases aren’t as well known as ours.”

However, some fear that emotive cases are swaying a debate that must be led by science, not the heart. England’s former chief medical officer, Dame Sally Davies, said earlier this year: “I think we have opened a Pandora’s box and there is a belief that it works for many conditions. I do have concerns about safety.”

The levels of THC – the psychoactive element in cannabis – in Stafford’s cannabis products touch 22%, which is higher than most skunk sold on the streets.

But Stafford said it was wrong to make the comparison. “When it’s in place of fentanyl, it doesn’t have the effect for me that it would probably have on a recreational user. It relaxes my body and makes my body bearable.”

Fears that medical cannabis prescriptions will be exploited to circumvent existing drug laws are also misplaced, according to Dr Rebecca Moore, a former consultant psychiatrist with the NHS who now works at the Medical Cannabis Clinic in London. She said desperate patients were travelling up to 400 miles for a consultation. “This is a last resort for patients who have tried everything else.”

Stafford is a volunteer at the United Patients Alliance which campaigns for medical cannabis to be made available on the NHS. She says that every day its Facebook discussion page carries posts from people saying that taking the drug has helped them get out of bed for the first time in months or to start exercising.

“We had a video from someone with Tourette’s and he filmed himself before and after medicating and it’s such an unbelievable difference,” Stafford said.

Prohibition Partners’ Curley suggested that 1% of the UK population could be medical cannabis patients by 2028. “Data from the ​British Medical Journal​ on patient numbers for 52 conditions potentially treatable with medical cannabis indicate an estimated patient base of over 4 million people,” she said. “Those numbers cannot and should not be ignored.”

Her consultancy predicts that the medical cannabis market in the UK, currently worth just £10m, could balloon to £1bn by 2024 – if NHS doctors start to emulate their counterparts in countries such as Germany and Canada and start prescribing.

But until then, Lucy Stafford, like many others, faces a dilemma: rack up debt or turn criminal. A return to fentanyl, though, is not an option.

“I was on opiates for seven years of my life. I could never imagine going back on to them now. The thought of that absolutely terrifies me.”

Who would it help?

The number of people in the UK suffering from conditions that are said to be alleviated by medical cannabis

Anxiety and depression One in four people (source: Mental Health Foundation)

Cancer 360,000 new cases each year (Cancer Research)

Crohn’s disease 146,000 (Crohn’s & Colitis UK)

Dementia (including Alzheimer’s) 850,000 (Alzheimer’s Society)

Epilepsy More than 500,000

Fibromyalgia 1.5-2 million

(Fibromyalgia Action UK)

HIV/Aids 100,000

(National Aids Trust)

Parkinson’s 145,000 (Parkinson’s UK)

Rheumatoid arthritis

400,000 (National Rheumatoid Arthritis Society)