The mother of a severely epileptic Co Tyrone boy has said the Government "have signed his death warrant" after halting his prescription for medicinal cannabis.
Billy Caldwell (11) from Castlederg used to suffer up to 100 seizures a day before 2016 when he began treatment with cannabis oil in the US, where medical marijuana is legal.
After a tireless campaign from his mother Charlotte, Billy became the first person in the UK to receive a prescription when his local GP Brendan O'Hare began writing scripts.
This was halted when the family doctor was summoned to the Home Office and told to desist.
Ms Caldwell has since travelled to London to meet MPs speaking at a conference on medicinal cannabis.
"We're just lost for words and absolutely devastated. The cannabis oil Billy was on was giving him an amazing quality of life and was controlling his seizures," she said.
"Without that, the Government have signed his death warrant because the seizures will return without the medicine."
Billy's current supply of medicine runs out in just three weeks, after which the family say they are at a loss at what to do next.
"We're taking it one day at a time now, I've travelled to London and we're appealing to the individual who signed Billy's death warrant to come forward," said Ms Caldwell.
The family have had the support of all the main political parties in Northern Ireland, but she said the DUP withdrew its support in recent weeks.
Jim Shannon is the DUP's health spokesman at Westminster and insisted the party was still committed to making prescribed cannabis legal, but said there was still a complicated legal process that had to be completed.
Mr Shannon has been in contact with the family of Sophia Gibson (6) from Newtownards, who also suffers from a rare form of epilepsy.
Her parents Darren and Danielle travelled to Holland last month to get the cannabis oil she needs.
"I've met the Home Office Minister Nick Hurd on this. He's sympathetic to the case but he's told us there's a process they have to go through," said Mr Shannon.
"The Home Office need to give us the go-ahead, so I'm still confident if we can get a strong medical voice to support us we can go ahead. It's still at an early stage so, to be honest, I don't see it going ahead right away, but I am confident that we will end up with cannabis oil available for all who need it."
In a statement, the Caldwell family said it believed "the Home Office are determined not to open the floodgates on this".
In England the family of Alfie Dingley, a six-year-old boy with epilepsy, have been engaged in a similar battle to legalise the medication through the courts.
Billy's family statement said the Home Office was trying to create a bespoke solution for Alfie without setting a precedent.
It added: "The Home Office have been trying to get off the hook for months with Dingley by coming up with a solution for him."
SDLP Foyle Stormont Assembly Member Mark H Durkan said: "I am appalled that the Home Office have reacted so heavy-handedly to a very sensitive and high profile case.
"It has been clear from the start that Billy's GP has issued this treatment in good faith to save a young boy's life, not to open the floodgates to inappropriate drug use."
"Medical professionals sign a Hippocratic Oath to ensure patients get the care they need, and this action by bureaucrats has undermined that oath," Mr Durkan added.