A mother locked in a legal battle to secure a medicinal cannabis prescription for her severely epileptic son has said they are "on a cliff edge" waiting for privately-sourced treatment to run out.
Charlotte Caldwell expressed fears that current arrangements where the medication is "gifted" on a week-by-week basis will be ended.
The Co Tyrone woman is seeking confirmation from the High Court in Belfast that cannabis can be prescribed to her 14-year-old son Billy on the NHS.
Proceedings were adjourned today for a letter on that issue to be sent to an expert in paediatric neurology at Great Ormond Street Children's Hospital in London.
Outside court, Mrs Caldwell said: "We're standing on the edge of a cliff, we know that the rock is going to give way, but we just don't know when.
"We're at the mercy of the manufacturer who is gifting us this medicine, we're at the mercy of the court, and we're at the mercy of these doctors."
Although Billy is currently receiving a product from a North American company free of charge, there are no guarantees over how long that arrangement will continue.
In November last year the rules were relaxed to allow some cannabis-derived medicines to be prescribed to patients in the UK by specialist doctors in limited circumstances.
It followed the high-profile case when Billy and his mother had cannabis oil brought back from Canada confiscated at London's Heathrow Airport.
The boy was then admitted to hospital after suffering seizures.
Despite the new guidelines, access to medication remains uncertain.
Mrs Caldwell brought a case against the Health and Social Care Board over an alleged failure to take a decision on the Canadian-sourced treatment.
She wants a declaration that a Northern Ireland-based GP or clinician who is not on the specialist register can lawfully write prescriptions for cannabis-based medication under the direction of a consultant paediatrician with higher qualifications in epilepsy diagnosis and management.
Mrs Caldwell also wants an assurance from the court that she can lawfully administer the drug to her son.
In court today her barrister, Monye Anyadike-Danes QC, said: "My client's greatest fear is something slips between the cracks and Billy runs out of his medication.
"He has not been without his medication bar one period when it was taken from him at Heathrow and he ended up in hospital."
Counsel for the Board said it cannot fund a private prescription, but stressed it will do as much as possible to help.
Adjourning the case to next month, Mrs Justice Keegan urged both sides to work together in an effort to find a solution under a shared care arrangement.
She told them: "Create a letter to send to Great Ormond Street, highlighting the issues you need answered, I want joint input into that."
