The family of a six-year-old boy have lost a bid to get permission to give him cannabis to treat a rare form of childhood epilepsy.
Alfie Dingley suffers a severe form of the condition which can trigger dozens of seizures every day.
His family say that using cannabis has helped to control his symptoms and has released him from what otherwise would be a "death sentence".
However the Government today turned down their bid to access the drug legally, saying it was "not recognised in the UK as having any medicinal benefit".
"This means it cannot be practically prescribed, administered, or supplied to the public in the UK," the Home Office said.
Alfie travelled to the Netherlands last September to try a cannabis-based medication prescribed by a paediatric neurologist, and saw his seizures reduce in number, duration and severity.
His family have since returned to the UK to continue fundraising for his campaign and to lobby for the licence to be granted.
The family's campaign was backed by MPs on the all-party parliamentary group on drug policy reform, who said he should be offered a way forward legally.
Crispin Blunt, co-chair of the APPG, said: "It would be heartless and cruel not to allow Alfie to access the medication he needs to make his life as seizure-free as possible and to keep him out of hospital.
Those pleas were rejected by the Home Office, which said it was not possible to bend the rules for a substance that was considered an illegal drug.
In a statement, a Home Office spokesman said: "We recognise that people with chronic pain and debilitating illnesses are looking to alleviate their symptoms.
"However, it is important that medicines are thoroughly tested to ensure they meet rigorous standards before being placed on the market, so that doctors and patients are assured of their efficacy, quality and safety.
"Cannabis is listed as a Schedule 1 drug, as in its raw form it is not recognised in the UK as having any medicinal benefit and is therefore subject to strict control restrictions.
"This means it cannot be practically prescribed, administered, or supplied to the public in the UK, and can only be used for research under a Home Office licence.
"The Home Office would not issue a licence to enable the personal consumption of a Schedule 1 drug."