More political parties are lining up firmly or cautiously behind cannabis decriminalisation - with even stronger backing for making the drug available for pain relief in certain medical cases.

There is also strong support among the public - around two-thirds support decriminalisation or legalisation of possessing a small amount of cannabis, according to a recent poll.

Decriminalisation means the drug would still be illegal, but offences punishable only by a fine with no criminal ticket, such as when a speeding ticket is issued.