AS THOUSANDS of young people danced in the sun at Britain’s Mutiny Festival on Saturday, two partygoers lay dying. Another dozen or so were sent to hospital. All are thought to have reacted badly to illegal drugs—and they will not be the last such casualties of the year. The death rate in Britain from ecstasy, a popular festival drug, is at its highest-ever level. Meanwhile deaths from opioids are on the rise across the rich world, particularly in America, where overdoses now kill more people than either cars or guns.

Many of these tragedies are avoidable—as another British festival last weekend showed. At a bash in Bristol, festivalgoers queued to have their illegal drugs tested by volunteer chemists, with the consent of the police. The checks revealed ecstasy pills that were four times stronger than average, pentylone masquerading as MDMA powder, unexpected cocktails of cocaine and ketamine, and other potentially deadly surprises. Such tests, growing in popularity around the world, offer a way to introduce basic safety checks to the chaos of the unregulated illegal-drugs market. Governments must encourage them if they are to turn the rising tide of needless deaths.

The prohibition of drugs means that people selling potentially lethal substances face fewer health-and-safety checks than people selling hot dogs. What is more, the secrecy under which the market necessarily operates inhibits the flow of information among consumers. Drug users have little chance of getting information on the quality of the mind-altering substances they are taking. Nowhere is that truer than at summer festivals, where customers buy from unfamiliar dealers who have little incentive to retain their loyalty.

The fog of war

Testing allows consumers to make a more informed choice. And it is catching on beyond the festival circuit. The Loop, the charity that carried out the Bristol tests, has begun to offer drug-checks in city centres. In America, some opioid users are being given strips to check for the presence of fentanyl, a highly potent drug responsible for many overdoses (see article). In Spain, an organisation called Energy Control analyses samples from anywhere in the world for a fee of €70 ($80), sending the results by e-mail with no questions asked.

Police officers, tired of scooping up limp young casualties of the drug war when they could be tackling real criminals, increasingly favour testing. But some politicians still worry that by making it safer to take drugs, they may be seen to condone or even encourage such behaviour. The same case is sometimes made against other forms of “harm reduction”, such as providing clean needles to heroin users, or giving them safe places to shoot up under supervision.

This is upside-down logic. The reason for discouraging drug use is that drugs are harmful, so it is perverse to argue that they should be kept harmful in order to discourage their use. In any case, the evidence so far suggests that, far from encouraging drug-taking, testing services seem to make people think twice. The Loop reports that 10-15% of the drug users it deals with decide to ditch their stash on learning what is really in it (which has included everything from concrete to anti-malaria medicine). A further 40-50% take less than they had planned. Governments, police forces and events-organisers should take note: to help people avoid the most harmful drugs, let them check what they are taking.