Tentative proposals to make slight cuts in cannabis penalties are being presented to the Home Secretary by his advisers this week. Behind the proposals lies the opinion of an expert sub-committee, which in an as yet unpublished report, says in effect that smoking cannabis does no particular harm.

Professor J.P.D. Graham, Professor of Pharmacology at the University of Wales, told the Advisory Council on the Misuse of Drugs: “On consideration, the technical sub-committee concluded that there was no compelling evidence that occasional moderate use of cannabis was likely to have detrimental effects on individual users.”

However the experts said that driving seemed to be impaired by cannabis smoking. It also seemed quite likely that heavy smoking would damage lungs much as cigarettes did.

The report says: “The available reports on the health of the individual of what is deemed to be long continued, heavy use of cannabis contain no evidence of consequential harmful effects on physical health. A casual relation between chronic use of cannabis and mental impairment was by no means proven…there appeared to be many compounding factors involved.”

These conclusions, in line with claims by the Legalise Cannabis Campaign and the move by American states which have reduced marijuana possession to a non-criminal “ticket” offence, led to a row in the full council.

It eventually voted to downgrade cannabis to Category C – the least dangerous group in British dangerous drug laws – and proposed by 16 votes to 11 that magistrates: should no longer have the power to imprison for simple cannabis possession; the maximum penalty in crown courts should fall from five years’ imprisonment to two; and the maximum penalty for trafficking from 14 years to seven. Cannabis possession would no longer be an arrestable offence.

The committee also proposed to upgrade Mandrax, an addictive sleeping pill, from Category C to Category B.

The full council, chaired by Sir Robert Bradlaw, submitted a report which added that there was a “world-wide conflict of views among experts.” Some people found the sub-committee’s conclusions “unacceptable.”

“In their opinion, cannabis could undoubtedly cause an acute psychotic reaction…whether cannabis was free from dependence potential (non-addictive) was now open to debate. The long-term risks of cannabis were “an open but worrying question.”

The council said that “social damage” caused by cannabis smoking might not be obvious.

The Legalise Cannabis campaign said yesterday that the proposed reforms would have little practical effect. Mr Tim Malyon of the campaign said: “Other foreign reports have laid out the pharmacological evidence so that a public debate can begin. This report does not do that, and is inconsistent in what it says. We want criminal penalties lifted.”

Source: January 1979: Cannabis Does Little Harm, Say Advisors to Government