MP Gordon Prentice has welcomed new trials using cannabis to relieve post-operative pain as another step towards returning the drug to the medicine cabinet.

The Pendle MP has been campaigning for the legalisation of "pot" and its derivatives in medical practice -- particularly to help sufferers from multiple sclerosis.

Many patients afflicted by the progressive nervous disease illegally use cannabis to relieve its symptoms.

The drug was only banned for medical use last century and Mr Prentice -- Chairman of the All-Party Multiple Sclerosis Group -- believes this decision should be reversed.

He is in favour of the legalisation of pills and substances derived from the cannabis plant for a range of medical uses.

Now the Medical Research Council is to spend £500,000 on a trial to see whether cannabis and related cannaboid products can relieve the pain of patients who have undergone surgery.

This comes on top of continuing clinical trials to see whether cannabis is sufficiently effective in relieving the pain and suffering of MS patients.

Mr Prentice said: "I welcome this new trial. It is a step towards returning cannabis to the medicine cabinet where it belongs.

"There is considerable evidence from MS sufferers that cannabis and its derivatives relieve their condition.

"If it is shown that cannabis is effective in relieving post operative pain, it should be available for use.

"I want to see qualified medical practitioners able to prescribe cannabis-based medicines under strict control where they would help relieve pain and suffering, especially in terms of MS.

"We do seem to be moving towards this and I shall continue to campaign in Parliament on the issue.''

The Leader of the MRC trial, Anita Holdcroft of Imperial Collge London, rejected claims that previous trials had shown cannabis-derived medicines no more effective than existing legal treatments for pain. She said they had not covered the ground her new experiments were going to do.

In 1998 and 2001 the influential House of Lords Committee on Science and Technology backed the legalisation of the use of cannabis and cannaboids for medical purposes.