Just 27 per cent of MPs were opposed to legalisation for medical use, the survey found.

The poll, conducted by Populus, surveyed a representative sample of 108 MPs, on behalf of VolteFace, a group campaigning for changes public policies on drugs.

It found 60 per cent of Labour MPs supported the use of cannabis for medical reasons, along with 55 per cent of Conservatives. Support from the Scottish National Party was most dramatic, with 88 per cent of MPs in support and none of those polled expressing any opposition.

In recent years, studies have increasingly supported the medical value of cannabis for treating conditions such as multiple sclerosis, epilepsy and arthritis, and for dealing with nerve pain.

Currently neither the Conservative nor Labour Party officially supports legalising cannabis for medical use.

Both the Green Party and Liberal Democrats have called for legalisation for medical use for some time.