That is an incredibly alarming story, because it was being prescribed presumably by an anaesthetist who knew exactly what they were doing. That was in the form of gas and air, but the people who misuse the drug use it neat, which is much more powerful and dangerous.

What used to require some effort to transfer smallish amounts from a canister to a balloon so that it could be used in a simple way is now something that can be inhaled all evening, sucking in huge quantities of nitrous oxide. Instead of being available in 8-gram canisters, it is now typically in canisters of up to 600 grams, which allows someone to sit there using it all night. The result is that doctors are now seeing an increase in cases of people being admitted to hospital with serious side effects.

Dr David Nicholl, a campaigner in my region of the west midlands—a local doctor and significant campaigner—tells me that he sees at least one new case every fortnight. Misuse of nitrous oxide creates a vitamin B12 deficiency. That is a vitamin vital for nerve function for both periphery in the hands and feet and in the spinal cord. Practical effects are numbness of the hands and feet and pins and needles, but longer-term use results in people being unable to walk and talk properly, relying on crutches and, in some cases, wheelchairs for, potentially, the rest of their life.