A drug which is said to "reboot" the immune system has been shown to be an effective treatment for multiple sclerosis (MS), a study has found.

Now the MS Society is campaigning for the drug to be available on the NHS.

The research showed that alemtuzumab significantly reduced the number of attacks or relapses compared to current drug interferon beta-1a. There are at least 10,000 people with MS in Scotland.

In one trial, new episodes were reduced by 49% more than the current standard treatment. Over a two-year period, 65% of patients on alemtuzumab compared with 47% of patients on interferon did not relapse.

"Our research shows the transformative effect alemtuzumab can have for people with MS," Professor Alastair Compston from the University of Cambridge said.

Doug Brown, head of biomedical research at the MS Society, said: "We urge Genzyme to price the treatment responsibly so that if it's licensed, it's deemed cost-effective on the NHS."