Britain’s most senior healthcare official has dealt the cannabis industry a blow by revealing grave concerns about the rollout of medicinal marijuana.

The UK legalized cannabis for medicinal purposes towards the end of 2018, but “cruel and ridiculous” NHS guidelines have prevented doctors from prescribing it for all but a handful of patients. The government is under pressure from various MPs, patients, and parents of suffering children to relax its stance and allow a proper industry to flourish.

However, NHS England chief executive Simon Stevens gave a speech to 300 doctors this week and revealed that he is not much of a fan of medicinal cannabis. “We have to be careful, as we have a legitimate national debate on medical cannabis, that we don’t look back in a decade’s time and wonder whether we inadvertently made a big mistake,” he said.

He pointed to the “well documented medical risks” from “so-called recreational cannabis” and said the government should be wary of “accidentally normalising drug use”. Stevens warned that medicinal cannabis could simply prove a gateway to adult-use legalization, which he opposes.

He revealed that he has just returned from a trip to North America and warned colleagues of a whole industry chomping at the bit to expand its tentacles into Britain.

The UK is the world’s fifth largest economy and it has the potential to be a major market for medicinal cannabis.

It is already big business in the country, as it is one of the world’s largest exporters of medical marijuana, thanks largely to British Sugar’s cultivation operation in Norfolk and the international success enjoyed by GW Pharmaceuticals (NASDAQ: GWPH).

The firm’s largest investor is Capital Group, which employs the Prime Minister’s husband, Philip May, as a relationship manager.

Campaigners for the liberalization of cannabis laws in Britain find this situation to reek of hypocrisy, and they continue to pile pressure on the NHS to change its guidelines, which were devised by the Royal College of Physicians and The British Paediatric Neurology Association.

Stevens did admit that there is a need to conduct research into the clinical uses of medicinal cannabis, although his comments will come as a blow to activists across the UK.