A CANNABIS-based drug that relieves the symptoms of multiple sclerosis is expected to be available on prescription by the end of the year.

GW Pharmaceuticals said Sativex, which contains extracts from whole cannabis plants, is on track for release, subject to approval by the Medicines and Healthcare Products Regulatory Agency.

Because it contains can-nabis, Sativex would require a change in the law, but Home Secretary David Blunkett has indicated he would be willing to make an amendment if the drug was approved