Medicinal cannabis can be prescribed for patients in the UK from today.
Doctors across England, Wales and Scotland will be able to prescribe the drug following a number of high-profile cases, which hit headlines earlier this year.
Experts say this could help tens of thousands of people who live with chronic conditions such as multiple sclerosis and epilepsy. It could also be used to treat people who are living with pain due to chemotherapy.
Until today, cannabis-derived medicines were only given to patients in exceptional circumstances, such as in the case of Billy Caldwell. Twelve-year-old Billy was granted permission to use cannabis oil by Home Secretary Sajid Javid to help treat his severe epilepsy.
Billy was suffering with up to 100 seizures a day, but his mother Charlotte says that after taking medicinal cannabis oil virtually all of his symptoms stopped and his quality of life vastly improved.
Prior to being given permission to use the oil, Charlotte had attempted to bring some into the country from Canada, but had it confiscated at Heathrow Airport.
Following talks with the Home Secretary, Billy was given the special licence, however, Charlotte vowed to continue fighting for other people in the UK who could benefit from the medicine.
Last month, a spokesperson from the government said: "We completely sympathise with the families who have been facing desperate situations as they try to find treatment.
"In July the Home Secretary committed to swift action on behalf of those whose medical conditions could potentially be eased by cannabis-based products and we have announced that cannabis-based products for medicinal use will be available for specialist doctors to prescribe legally from the Autumn.
"In the interim the expert panel will consider applications for these products. Any proposed course of treatment with cannabis-based medicine must be clinically led."
Charlotte said she was delighted with the decision.
"It's been a treasure just out of reach for what seems like forever," she said. "But to see it in writing from the Government is incredible. This isn't about Billy and me, it's about a nation.
"Only relatively recently did our Government and country really start to appreciate just how many wee children and people of all ages were affected by the difficulties associated with accessing medicinal cannabis.
"But once it became clear that it wasn't just about what was perceived to be a small number of very sick children, and that medicinal cannabis could make a life-changing or life-saving difference to more than a million people, the overwhelming support of the public and the incredible speed of reaction of the Home Secretary has delivered an utterly amazing result.
"It feels like both five minutes and five years since Billy and I landed at Heathrow on June 11 and his meds were confiscated.
"Within a week, the Home Secretary had recognised the gravity of the situation for both Billy, and potentially many more children, then many families, then thousands of other people.
"What started out as a journey for me as Billy's mummy to help my little boy has become something much bigger.
"The needs of my little boy turned out to be the needs of many more."