Legalising cannabis for medicinal purposes would reduce the drug’s side effects, MPs have heard, as a fresh attempt to change the law was brought before the Commons.

Labour’s Paul Flynn said the “tide of world opinion” was moving towards legalising the class B substance which he described as the “oldest medicine in the world”.

He acknowledged cannabis side effects exist but said there had been “no problems” that have arisen in countries which have legalised the drug for medicinal purposes.

Mr Flynn said: “If we do legalise drugs we reduce the side effects by taking the market out of the hands of the criminals and the scammers, and put it into a legal market that can be run by doctors on medical priorities.”

Moving his Legalisation of Cannabis (Medicinal Purposes) via a 10-minute rule motion, the former frontbencher said he had the support of the MS Society and two Police and Crime Commissioners for the move.

Mr Flynn said: “It’s time for us, I believe, to lead public opinion rather than follow it.

“I believe it would be an act of compassion and courage for us today to pass this Bill and allow the change – and it’s a very minor change – moving the cannabis from schedule one to schedule two, because at the moment the law says that cannabis has no beneficial effects and we all know it does.”

Paul Flynn with campaigners outside ParliamentPaul Flynn with campaigners outside Parliament (Stefan Rousseau/PA)

The Newport West MP dubbed the legislation the “Elizabeth Brice Bill” after the multiple sclerosis (MS) sufferer who campaigned as Clare Hodges for the legalisation of medicinal cannabis before her death in 2011.

He was given permission to bring in his Bill and he asked for it to be given a second reading on February 23.

It is unlikely to become law in its current form without Government support or sufficient parliamentary time.