A legitimate argument?
Would UK ministers and officials really claim that a range of NHS-approved drugs have no "legitimate use" in order to justify an EU opt-out?
NHS England alone spends more than £200m a year on the drugs - used to treat Parkinson's disease, epilepsy, depression and insomnia - but Home Office minister Norman Baker has told parliament that "very little" legal trade in the medicines takes place.
The apparently preposterous British position comes about because, to admit these substances are marketed legitimately, would fundamentally undermine the UK's argument this week for claiming an opt-out from proposed European regulation of "legal highs".
A Home Office official has told me the UK government does not believe medicines should be included as a "legitimate use" for substances identified as legal highs.
This week the crime prevention minister Norman Baker announced that the government had decided to opt out of proposals for a directive on new psychoactive substances (NPS), fearing that they would "fetter the UK's discretion" to control legal highs.
The prospect of press stories about "Eurocrats" telling the Home Office how tough they could be on legal highs is a nightmare for the UK government. "Member states should not be prohibited from unilaterally introducing more stringent controls for NPS," Mr Baker argues.
In a ministerial statement this week he explains how the coalition government "strongly dispute the evidence base stated in the EU Commission's impact assessment which estimates that 20% of new psychoactive substances have a legitimate use".
This is a key part of the government's legal justification for opting out. Without a significant legitimate trade in NPS, questions over the single market disappear.
The Commission has argued for a Europe-wide directive on legal highs because it says different approaches across the EU "can impede their legitimate use… and fragment the internal market".
The Brits refuse to accept there is much "legitimate use" for substances notified to European authorities as NPS.
"Our evidence suggests the trade is overwhelmingly illicit," Mr Baker told a Lords Committee last year, "and therefore it is difficult to argue that this is a trade measure, when there is very little legal trade taking place on this basis."
However, the EC has produced a long list of all the uses and potential uses of substances flagged up to EU drug monitors as worrying legal highs.
Among them is Pregabalin, notified as a legal high in 2009. In 2012, NHS England alone spent more than £181m on the drug as a treatment for epilepsy, sometimes under the trade name Lyrica. The European market is worth considerably more.
Another substance notified to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) as a potential legal high is Aminoindan, from which a drug used in the treatment of Parkinson's disease, Azilect, is derived. The health service spends around £9m a year on the treatment.
Again, ministers argue there is no significant legitimate trade in Aminoindan.
Another substance identified as a legal high, ODT, is a metabolite of the pain relief tablet Tramadol. NHS England spent £33m on such pills in 2012.
The Home Office itself notified the European authorities that Zopicline was being sold as a legal high. The NHS in England spends around £4m on Zopiclone as a treatment for insomnia each year and it is sold across the EU.
NHS England also spends around £250,000 on Nefazodone and Trazodone - drugs used for treating depression which include notified legal highs among their ingredients. Again, UK ministers appear to be claiming the substances should not be regarded as having "legitimate use".
It is hardly surprising that prescription medicines and potential treatments should also be turning up as legal highs. To recognise their medical use does not prevent UK ministers from introducing tough penalties for their illegal sale and possession. After all, diamorphine (heroin) is widely used within the NHS and is also a class A illicit drug.
It does, though, make it much harder to claim the legitimate market is "minimal at best".
The Swedes in 2011 alerted the authorities that Ostarine was being sold as a legal high. The NHS has suggested the drug has the potential to be an exciting new first-line therapy in the treatment of patients with lung cancer. Home Office ministers, though, dare not accept that the substance has a potential market across the EU.
Etizolam was identified as a legal high by the UK in 2011, a substance sold in chemists across many countries as a treatment for insomnia and anxiety. The Home Office also notified European drug monitors about Glaucine, a drug used in parts of Europe as an ingredient of cough medicine.
According to the European Commission, there are dozens more examples of substances currently being monitored as potential legal highs which have medicinal uses or properties.
And yet a Home Office official, David Greaves, told a House of Lords committee that, apart from two industrial cleaners and a "small number" of substances used to make medicines, "none of the other approximately 300 new psychoactive substances that have been reported to the EMCDDA have commercial or industrial uses".
There is a clear difference between the UK argument that legitimate uses for legal highs are "few and far between" and the EC argument that "the size of this market is considerable".
According to the Commission, almost a fifth of all new legal highs notified since 1997 have other uses, adding that, since data on legitimate use is not systematically collected, this may well be an underestimate.
I contacted the Home Office to ask how they could come up with such a different conclusion from the European Commission. A press officer tells me: "We disagree with how the Commission has defined legitimate use. They have included medicines and potential medicines. We don't think medicines should be included."
I am still awaiting a response to that question. But I think I know the answer. It is not because Norman Baker truly believes there is no legitimate use for a cancer drug or a market for an insomnia treatment. That is a ridiculous claim.
It is because, as Mr Baker said, "the proposed NPS regulation… is a harmonisation measure". And if avoiding that horror requires UK officials and ministers to claim NHS-prescribed medicines for epilepsy and Parkinson's disease have no legitimate use, then that is just what they will say.