The Government refuses permission to use the drug despite previous treatments helping ease the boy’s persistent seizures.
A six-year-old boy who can suffer up to 30 seizures a day has been denied permission to use cannabis.
Alfie Dingley, from Warwickshire, has a rare and extreme form of epilepsy.
His parents want to treat him with cannabis oil, which is illegal in the UK.
In September, he and his parents, Hannah Deacon and Drew Dingley, went to the Netherlands so he could take a cannabis-based medicine prescribed by paediatric neurologist.
This reduced his seizures in number, duration and severity.
But the family could not afford to continue the treatment and had to return to the UK where they concentrated on lobbying for a cannabis licence.
The Home Office has now denied the licence, saying that the drug “cannot be practically prescribed, administered or supplied to the public”.
The decision comes despite support from some MPs, including those in the all-party parliamentary group on drug policy reform.
Alfie’s seizures can be controlled in hospital but his long-term prospects include being institutionalised with psychosis.
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.”
Alfie’s grandmother, Maggie Deacon, said by using the oil he had “gone from a death sentence to the prospect of a more normal life with school, friends and fun in his own familiar home”.