Sir Keir Starmer’s latest intervention in the drug policy debate shows just how woefully incoherent the whole thing has become. The Labour leader backs Scotland’s decision to start issuing warnings to people caught in possession of Class A drugs, but not actually overhauling the law.

This has been done to try and make a dent in Scotland’s horrifying drugs deaths statistics, although it isn’t obvious that it will do this. It could make people less reluctant to seek help if they get into trouble; it could also just encourage more people to take drugs.

Likewise, relying on case-by-case decisions by officers is an unreliable way to deliver meaningful change.

One potential upside of the decision is that the police could initiate the de facto breakup of the nonsense category that is ‘Class A’. There is no sensible case for treating LSD (‘acid’) or MDMA (‘ecstasy’) the same as heroin or meth. They are completely different substances with very different user bases and threat profiles. Most MDMA deaths are artefacts of prohibition, either because people didn’t know what they were taking or were reluctant to seek help; LSD basically doesn’t kill people at all.

The negative externalities of the criminal trade – which feature heavily in Priti Patel’s attack on Starmer’s decision – are also different when the drug in question is synthesised in the Netherlands rather than harvested in Latin America, Afghanistan or the Golden Triangle.

But without updating the actual legislation governing these substances, there is no guarantee of this wiser approach. It also means that many of the potential upsides of actual decriminalisation, such as allowing nightclubs to host drugs-testing facilities to stop ravers taking poisonous pills, will remain off-limits.

Meanwhile the signal sent to consumers is strong and clear. The SNP’s approach risks getting many of the downsides of decriminalisation with fewer of the upsides.

It’s unfortunate that Starmer has opted for such a weak position on this question. For Nicola Sturgeon and her ministers, making changes to police guidance makes tactical sense because it minimises scrutiny from MSPs and avoids having to divert resources from what they really care about: independence.

The Leader of the Opposition does not face the same constraints, and could if he chose set out a bold and intellectually-coherent approach. That need not be decriminalisation – a ‘Goldilocks’ policy that has serious drawbacks – but it would be far better than just rowing in behind the SNP. If a politician with his background can’t come up with some interesting proposals for reforming the criminal law in such an important area, then who will?