First it was MCat. Then it was Spice and Benzo Fury. Now AMT, 2-MK and ethylphenidate are marketed online as legal substitutes for cannabis, ecstacy and other banned substances. These compounds are part of the new phenomenon of legal highs: synthetic substances that mimic the properties of illegal drugs but whose chemical structures have been carefully crafted to fall outside the scope of existing drug laws.

And demand is growing. In addition to the unpalatable risk of arrest associated with illegal drugs, two factors favouring legal highs are price and purity. Compared with banned substances, which can contain as little as 10 per cent of the active compound, legal highs are close to pure and can be bought for less than a quarter of the price of their illegal counterparts.

While the increased use of designer drugs has consequently led to an increase in related deaths, the government’s line on legal highs has been disappointingly reactionary. In 2010, MCat and other synthetic amphetamines were banned. Further complexity was introduced in June 2013, when a Temporary Class Drug Order outlawed two further designer drugs for a period of 12 months.

The strategy of “adding inexorably to the list of illicit substances” is a serious overreaction and unpopular with many political advisors and medical professionals. A more level-headed solution comes from the All-Party Parliamentary Group for Drug Policy Reform. Their regulated approach puts “the onus... on the supplier of a new drug to demonstrate a low risk of harm,” and would allow restricted distribution of “low risk” substances.

Like any psychoactive substance, legal highs clearly require careful evaluation to determine possible risks to health. However, hysterical prohibition of all compounds should not be favoured over a rational, evidence-based approach. The growth in the use of legal highs presents a unique opportunity to reform our clunky and outdated drugs legislation.

When many legal highs can be considered less dangerous than substances used daily in our society, such as alcohol, an outright ban can never be more than an attempt to curtail freedom of choice and individual liberty.