The case of Billy Caldwell, the 12-year-old boy with a rare form of epilepsy that can be treated with cannabis oil hit the headlines this week, igniting a debate about the use of medical marijuana, which is illegal in the UK.
Former foreign secretary William Hague said the class B drug should be completely legalised, while home secretary Sajid Javid stressed that it should remain banned for recreational use, and on Tuesday announced that the Government would review the law on medical cannabis, which could lead to patients in Britain being prescribed the drugs.
Cannabis oils are extracted from the cannabis plant, which has more than 100 cannabinoids. The two main active cannabinoids are cannabidiol, or CBD, and tetrahydrocannabinol, or THC. CBD does not have an intoxicating effect, while THC is a psychoactive chemical.
A spokesman for the Cannabis Trades Association UK said that there were no side effects to taking CBD, and never had been, unlike THC.
There are currently more than 365,000 confirmed users of cannabis oil in the UK. Most are in the 40-70 year old age range, and 60pc of them are women.
Most studies of CBD’s effects are pre-clinical, but it has been shown to be useful in treating anxiety, lessening episodes of schizophrenia, treating childhood epilepsy and neuropathic pain, as the chemical has an anti-inflammatory effect and encourages the release and uptake of dopamine and serotonin.
While medical marijuana is illegal, the Medicines and Healthcare products Regulatory Agency (MHRA) determined in 2016 that products containing cannabidiol can be prescribed.
So far only a very small number of cannabis-based drug treatments are approved for use in the UK. Sativex, a peppermint-flavoured mouth spray that is a 50-50 mix of THC and CBD is an approved treatment to ease loss of muscle control in people with multiple sclerosis, but it is costly and rarely prescribed.
CBD products, including oils and supplements, are completely legal in the UK because they do not contain THC. CBD is not controlled under the Misuse of Drugs Act 1971 so in its pure form it does not require a licence from the Home Office.
These CBD oils can be easily bought online and are becoming increasingly popular.
"Every day the stigma around cannabis oil lessens, and the market is growing all the time. A few years ago it was worth around £10m-£12m, but today it's worth £60m, and will be £100m in the next couple of years," the Cannabis Trades Association spokesman said.
CBD Oils, the UK's largest retail suppliers of CBD, says it had seen a "sharp increase" in sales over the past 12 months, with the number of products sold doubling year-on-year. Tony Calamita, the company's managing director, said it was processing around 2,500-3,000 purchases a month.
Its CBD hemp droplet-infused water (£1.99), which contains 2mg of active CBD and was launched earlier this year, is currently stocked in Ocado and is about to launch in Holland & Barrett.
"This is the first cannabis water in Europe and the first ever to launch in a supermarket. It's great that British retailers are normalising cannabis-based products and making them accessible to consumers," Mr Calamita said.
The company is currently working on a range of edibles, Mr Calamita added, and has an agreement with high street retailers to stock them. He stressed that the products would contain CBD and not THC, so they would not be able to get people high.