Image caption Cannabis oil is used to control Billy Caldwell's seizures

A County Tyrone boy has returned home after the Department of Health issued an emergency licence allowing doctors in Belfast to treat him with medicinal cannabis.

Billy Caldwell, who is severely epileptic, has been receiving treatment in London.

The department replicated the licence issued in June by the Home Office.

Billy and his mother Charlotte returned to Northern Ireland on Thursday afternoon.

On Tuesday, the government said it would reach a decision within the next few weeks on whether laws around medicinal cannabis would be changed.

Billy's story was one of a number of high-profile cases which prompted the government to review the its use.

Arrangements in place

On Wednesday, the Department of Health in Northern Ireland received an emergency licence application from Belfast Trust clinicians regarding medicinal cannabis use for Billy.

In a statement the department said Billy's medication would arrive in Northern Ireland on Thursday and "arrangements are in place to administer it on Thursday evening and thereafter."

The trust added that it had been in touch with Ms Caldwell to discuss this with her and that doctors at a Belfast Trust hospital would be responsible for the medication.

"We have also been in discussions with the Home Office to finalise arrangements for the immediate transportation of Billy's medicine from London to the Belfast Trust," a Department of Health spokesperson added.

Billy began using cannabis oil in 2016 to control his seizures.

The oil, which contains a substance called Tetrahydrocannabinol (THC), is illegal in the UK but available elsewhere.

Speaking to BBC News NI Ms Caldwell said she hoped Billy's medication could be administered to him at home, rather than at a Belfast hospital, in the near future.

She said: "It would be that a community nurse would come to our home and administer the medicine at hour house twice a day.

"That way I would feel I would be protecting Billy because he would be at home in his own surroundings."

Image copyright Getty Images Image caption Cannabis oil is not licensed in the UK as a medicine

Does cannabis have medicinal benefits?

CBD and Tetrahydrocannabinol (THC) are two types of cannabinoids found naturally in the resin of the marijuana plant.

A cannabis-based drug called Sativex has been licensed in the UK to treat MS. It contains THC and CBD.

Doctors could, in theory, prescribe it for other things outside of this licence, but at their own risk.

MS patients prescribed Sativex, who resupply it to other people, also face prosecution.

Another licensed treatment is Nabilone. It contains an artificial version of THC and can be given to cancer patients to help relieve nausea during chemotherapy.

Source: NHS Choices