IN THE restless pursuit of pleasure, human beings will try almost any substance when circumstances require. During prohibition, Americans resorted to drinking toxic moonshine and inhaling ether. Second-rate substitutes and legal highs are seldom as pleasant as the real thing and are sometimes more dangerous, but at least you don’t have to worry about getting arrested.The designer drugs that have swept Europe in the last two decades are the modern equivalent of moonshine, aided by the growth of the internet and the waning purity of ecstasy pills. Between 2003 and 2008, the MDMA content of ecstasy fell from 67 per cent to 33 per cent at a time when illicit chemists were synthesising dozens of new recreational substances. Ketamine, GHB, GBL, BZP and mephedrone all generated their own minor moral panics and were banned, only to be replaced by the likes of naphyrone, MDAI and Ivory Wave. More will follow. Twenty-four new legal highs were synthesised in 2009, with a further thirty-three appearing in 2010.Although billed as “party drugs”, these chemicals often have little in common. Clubbers might use them interchangeably but mephedrone (Meow Meow) and BZP are stimulants, while GHB and ketamine are heavy sedatives. Different in nature and unpredictable in potency, users are vulnerable to overdose. Naphyrone (NRG-1) is active at just 20 milligrams while mephedrone is active at 200 milligrams. Since naphyrone was touted as “the new Meow Meow” when it appeared in 2010, users were liable to take ten times the “safe” dose. Some did.Despite immense efforts by police, customs officers and legislators, there has been no decline in the nation’s consumption of illicit chemicals since the ecstasy panic peaked fifteen years ago. What we have instead is an ever-widening menu of narcotics about which users and authorities know little.One proposed solution is to introduce a law similar to the USA’s Analog Act which automatically bans drugs which are “substantially similar” to banned substances. The idea is tempting in its simplicity, but this Nixon-era legislation is too vague to be legally useful and has rarely been invoked. The grey market continues to be one step ahead of legislation.An alternative solution was proposed last week by Dr James Bell, of the South London and Maudsley NHS Foundation Trust, who suggested abandoning the unwinnable war against chemistry in favour of legalisation. All calls for drug liberalisation fall on stony political ground and Bell’s was no different, but there would be no better way of stopping the flood of dubious chemicals than a regulated free market. These drugs are nobody’s first choice. BZP was originally a worming tablet for cattle. Ketamine was a veterinary anaesthetic. GBL was a superglue remover. In all likelihood, that is what they would have remained had ecstasy not been banned.Nobody made 80 per cent proof gin in their bathtubs after prohibition was repealed in 1933. Instead, Americans turned from distilled spirits to beer, the number of alcohol poisonings fell and the murder rate subsided. There is a lesson there for those fighting against narcotic moonshine today.Chris Snowdon is an author and freelance journalist. His latest book is The Art of Suppression: Pleasure, Panic and Prohibition Since 1800.