A climate-controlled facility in the Midlands grows rows of genetically identical cannabis plants, each exactly 1.5 metres high, under lighting that never varies by more than half a degree. The operation, run by Dalgety, holds licences from the Home Office and the Medicines and Healthcare products Regulatory Agency (MHRA). Its chief executive, James Leavesley, says the farm produces enough for 4,000 prescriptions a month and has attracted £12 million in investment so far, with plans to serve 22,000 patients. Security is provided by former soldiers, and an armed police response is on standby.
A regulated facility in the Midlands
Dalgety is one of only four companies licensed to cultivate cannabis legally in Britain. Its non-executive directors include Jane Sawyers, a former Staffordshire chief constable, and, until she became a minister last year, former Labour Home Secretary Jacqui Smith. When Sajid Javid, then Home Secretary, legalised medicinal cannabis in November 2018 after a campaign by parents of children with epilepsy, this type of rigorously tested, domestically grown supply was broadly what Parliament envisaged.
The gap between regulation and reality
Seven years on, the £300 million market looks very different. Most British patients do not receive products like Dalgety's. Instead, they obtain imports of ultra-high strength cannabis flowers from American and Canadian brands whose names, "Fuck Around and Find Out", "Haymaker Haze", emphasise recreational appeal. The latter is fronted by former boxer and convicted rapist Mike Tyson. Few are supplied in medicinal forms such as capsules; most are sold as flowers to be vaped or smoked.
Although non-medical cannabis remains a Class B drug under the Misuse of Drugs Act, private clinics legally prescribe these lifestyle brands. The Advisory Council on the Misuse of Drugs announced only last Thursday that it will investigate whether the 2018 changes have had their "intended impact" and identify any "unintended consequences".
Private clinics drive prescription surge
The 2018 regulations allowed any doctor on the General Medical Council's specialist register, roughly 140 physicians, to prescribe cannabis privately for any "unmet clinical need". The rules do not restrict the conditions that qualify, nor do they cap the potency of what can be prescribed. Advertising the drug is unlawful, and prescriptions are supposed to rest on "purely therapeutic considerations", according to Professor Trevor Jones, a former government adviser who led research at the Wellcome Trust.
In practice, the market has exploded. Private clinics and pharmacies dispensed just 4,000 prescriptions in 2020. By the year to March 2024 that figure had risen 130 per cent to 346,000, following a 119 per cent jump the previous year. Legal imports more than doubled in 2024. Industry sources estimate 75,000 patients nationwide. The Care Quality Commission (CQC) recorded fewer than five NHS prescriptions in 2022-23.
There are now 43 cannabis clinics in the UK. Mamedica, which announced a £4.5 million investment from rapper Snoop Dogg, claims 7,500 patients. Mike Barnes, co-author of the 2016 parliamentary report that helped pave the way for legalisation, runs Maple Tree consultancy, which has advised more than 300 clinics, pharmacies and distributors. Clinics collectively prescribe for over 70 conditions, including anxiety, depression, chronic pain and psoriasis. Most operate entirely online: a written survey followed by a short video call replaces a face-to-face consultation. An initial appointment costs about £100; some patients pay more than £2,000 a month for cannabis.
High-potency products and psychosis risk
Professor Sir Robin Murray, one of the world's leading authorities on cannabis and psychosis, treats patients at Britain's only dedicated cannabis psychosis clinic at the Maudsley Hospital in London. He describes a young man who had stabilised after treatment but relapsed into psychosis after being prescribed medical cannabis from a private clinic. The prescribed product was far stronger than the illicit cannabis he had used previously. More than a year later, the patient remains sectioned under the Mental Health Act.
If the dried leaf marijuana found in Britain 40 years ago was just 3% THC, which Murray likens to a weak draught lager, private clinics now regularly prescribe cannabis 10 times as strong.
No reliable statistics track how many medicinal cannabis patients develop psychosis. However, international evidence shows frequent use of high-strength cannabis raises the risk substantially. The Lancet has found that smoking high-THC cannabis daily increases the risk of psychosis by at least 400 per cent. Remarkably, UK law sets no limit on a prescription's potency.
Clinics say they screen out patients with a personal or family history of psychosis. Yet research indicates that individuals with no prior mental health issues who "self-medicate" with cannabis are actually more likely to develop problems later.
Celebrity brands and marketing concerns
Despite the advertising ban, Mamedica promotes its partnership with Cookies, a US recreational brand founded by rapper Berner, whose album Hempire celebrates cannabis culture. Cookies strains available via Mamedica include "Hawaiian Rain" at 31 per cent THC. A review site, Strains UK, describes it as providing "an enjoyable head high and a relaxing body stone". In June, Mamedica released a promotional video featuring comedian Dom Joly using euphemisms such as "hippy broccoli" and "stuff". The voiceover closes: "Talk to the experts if you're considering alternative healthcare. Mamedica, for safe, legal care you can trust."
Mike Tyson's "Tyson 2.0" range, including the 28 per cent THC "Haymaker Haze", is grown in North Macedonia and distributed in Britain by PHCann International. Its chief executive, Sasho Stefanoski, said last year that the partnership meant "we can lead the charge in pushing industry boundaries".
Andrew Tyler, Mamedica's chief executive, insists the clinic runs a "rigorous eligibility process" with safety as the "overriding consideration" and does not prescribe where there is any personal or family history of psychosis. Ralph MacMurray, founder of Medbud.wiki, counters: "you can't really separate recreational and medical use".
Regulatory response remains limited
Some industry figures acknowledge the risks. Graham Woodward, a former psychiatric nurse who heads Releaf clinic, refuses to prescribe cannabis above 25 per cent THC and is gathering data for a clinical trial on long Covid. Mike Barnes also says he opposes strains stronger than 25 per cent THC and criticised the "pseudo-recreational market" last year. Yet he is a Mamedica shareholder whose strongest strain reaches 34 per cent THC, and he maintains that with careful prescription the dangers are "minimal", a claim that prompts Professor Sir Robin Murray to suggest he visit some of his patients.
Official bodies have been slow to act. The CQC called for a multi-agency inquiry last year; it was ignored. Professor Trevor Jones recently lobbied the Home Office and the MHRA, which must approve every cannabis import, and received no response. He also asked the General Medical Council to investigate the role of specialist doctors. The GMC replied that it "is not an inspectorate, and we do not proactively monitor compliance with our professional standards".
James Leavesley of Dalgety notes that 1.8 million people already use illegal cannabis for medical reasons. If even half switched to legal prescriptions, he says, "the market would be huge". Mike Barnes estimates 2-3 per cent of the population, about two million people, could "potentially benefit". As the Advisory Council begins its review, the bonanza continues with minimal guardrails.