A former senior UK government advisor on drugs policy has joined calls for a debate about the decriminalisation of controlled substances to begin in Scotland.

Professor David Nutt, who is currently the Edmond J Safra chair in Neuropsychopharmacology at Imperial College London, was dismissed as chair of the Advisory Council on the Misuse of Drugs in 2009, after saying that ecstasy, cannabis and LSD were less dangerous than alcohol and tobacco.

He has long advocated the use of some illegal substances to treat patients suffering from everything from anxiety attacks to terminal cancer, but admits he has struggled to garner political support at Westminster.

Nutt has now urged the Scottish Government to examine what devolved powers could be used to open up the possibility of prescribing controlled substances such as cannabis.

Although the criminal control of drugs is a policy reserved to Westminster, Nutt believes the Scottish government could tinker with drugs policy in Scotland by following a medical route. The Scottish government however says it has no power over the medicinal use of drugs.

Mike McCarron, a former Scottish government adviser and member of campaign group Transform Drug Policy Foundation Scotland, and Patrick Harvie MSP, co-convener of the Scottish Green Party, recently called for a debate about decriminalisation following a series of Sunday Herald investigations into the failure of the so-called War on Drugs.

Nutt said: “The SNP are painting themselves to be radical and progressive and I would be delighted to have a dialogue with them. I would offer myself and my [academic] team to help them develop more rational policies.

“My first priority would be to decriminalise cannabis and make it available for medical use so that people would stop using opiates. We know it works. The Dutch have done it for 35 years. It’s completely safe, so just do it. Personally I would decriminalise the possession of all drugs.

“If you’re proud to be Scottish you should be proud of Scottish scientific heritage and you should be encouraging the Scottish discoveries – particularly around cannabis and opiates – to be easy to translate into medicines, but you’re not at present.

“The British laws don’t allow that but if the Scottish Government was to change Scottish laws you’d progress much more rapidly.”

Westminster is responsible for setting out the legal status of substances classified under the Misuse of Drugs Act 1971.

Substances are placed in one of five schedules based on an assessment of their medicinal or therapeutic usefulness and the need for legitimate access.

Nutt has had little success in persuading MPs to alter policy and has now turned his attention to Scotland’s parliamentarians.

He said: “I’m fighting Tories, Labour and everyone else (at Westminster). The only people that are sane about drugs policy are the Liberal Democrats, and there’s only eight of them, and the Greens, and there’s one of them. So, you’re in a terrible minority.

“We must start the debate in Scotland. I would welcome it with open arms because you could change the laws for medical cannabis. If you made cannabis a medicine in Scotland tomorrow you could bring in billions in terms of health tourism. It would be like having a blank cheque. But the SNP haven’t thought it through at all.

“They should change the scheduling so that people can research them more readily. There’s a difference between researching them and having them as medicines. If you change the scheduling then they can at least be researched.

“That doesn’t mean they can be licensed as medicines – although personally I think the Scots should just say they can be used as a medicine by doctors who know all about it – but even if they don’t want to go that far they could change the scheduling so that any hospitals can research it without a special licence.”

The Scottish Government has previously said it would not seek to alter drugs policy even if it was devolved to Holyrood.

The Irish government recently announced a "radical culture shift" which will see possession of drugs decriminalised in ordered to focus on offering help to addicts and users rather than punishing them with criminal convictions and prison.

Nutt has urged Scotland to follow Ireland’s lead and become the first nation in the UK to take a fresh approach.

He said: “Scotland has a devolved health service and they can do whatever they like as far as I can see. Scotland makes decisions about its own medicines. It needs someone to say we’re going to do it argue the case. It would take some balls but someone with balls should do it and start the debate.

“There’s no point in asking the Home Office because they’ll say no. But I actually do not think this is their jurisdiction anyway. I think it is fully in the jurisdiction of the Scottish Government and I don’t think the Home Office could do anything about it. That’s my view and I would be interested in speaking to anyone who wants to challenge it.”

A Scottish Government spokesman said: “The classification of drugs is currently reserved to Westminster – however, even should we gain responsibility for the issue, we have no plans to support the legalisation or decriminalisation of drugs. The medicinal use of drugs is a separate issue, which is also currently reserved to Westminster.”