Louis Wainwright, 18, and Nicholas Smith, 19 tragically died in March this year following a night out in their home town – their deaths leading to widespread concern and media hype around the drug, M-Khat, which they had reportedly taken, and providing significant support for a witch-hunt that led to its subsequent and rapid illegal classification.
The latest news, according to former Chief Drugs Adviser Professor Nutt – who himself resigned over government drug policy in October 2009 – significantly undermines the justification of the ban.
He told BBC News: "If these reports are true, the previous government's rush to ban mephedrone never had any serious scientific credibility - it looks much more like a decision based on a short-term electoral calculation.
"This news demonstrates why it's so important to base drug classification on the evidence, not fear, and why the police, media and politicians should only make public pronouncements once the facts are clear."
Further tests will now be carried out to find out what substances – if any – the pair had taken. Police reported at the time that pair had taken heroin substitute methadone, but that is yet to be confirmed.
Meanwhile, current chair of the Advisory Council on the Misuse of Drugs (ACMD) Professor Les Iverson, insists the meph ban was justified, despite this new evidence: "The ACMD gathered evidence from a number of experts and thoroughly researched the cathinones including mephedrone before making its recommendation.
"On the basis of this evidence, and in comparison with similar substances, it concluded that the harms associated with cathinones equate to other dangerous substances in Class B, particularly amphetamines which are structurally similar and act on the central nervous system in the same way."
Mephedrone has been linked to 26 deaths in the UK so far, but only once has it been shown to be the cause of death. This latest shock news will only serve to fuel concerns that the previous government's reactionary drug policy was out of touch and unhelpful - a fact that the current government may be forced to deal with.