A cannabis-based treatment is set to be trialled on hundreds of patients in the hope that it can extend the life of people suffering with a terminal and highly aggressive type of brain tumour.

       The drug, called Sativex, is an orally administered spray that contains both CBD and THC and is used to help treat some muscular sclerosis patients.

       The new study will investigate whether, in conjunction with chemotherapy, it can extend the lifespan of people suffering with recurrent glioblastoma, the most common form of brain tumour.

       Currently, the average survival for people who are told they have a glioblastoma is 10 months. Around 2,200 are diagnosed in England every year.

       A total of ￡450,000 is needed to launch the phase two human clinical trials, which will take place at 15 hospitals and involve more than 200 patients.

       The Brain Tumour Charity is trying to raise the sum and has received the support of Tom Daley, the Olympic champion diver, whose father died of a brain tumour in 2011, aged 40.

       In a video to promote the trial, Daley said: "We are reaching out to all you individual heroes and supporters to help fund this groundbreaking trial."

       The trial is set to build on promising preliminary results released earlier this year, when it was found the drug can give sufferers "precious extra time to live" after a glioblastoma diagnosis.

       The next step will investigate whether adding Sativex to chemotherapy extends the overall length of patients' lives, delays the progression of their disease or improves quality of life.

       Susan Short, professor of clinical oncology and neuro-oncology at the University of Leeds, said: "It's really exciting that we're now at the point where we can run a definitive, well-designed study that will tell us the answer to whether these agents could help treat the most aggressive form of brain tumour."