Two "legal high" chemical compounds marketed as Benzo Fury and NBOMe are to be temporarily banned for up to 12 months, Home Office ministers have announced.
The two new psychoactive drugs are to be made illegal while the government's advisory council on the misuse of drugs assesses whether the ban should be made permanent. The temporary banning order laid before parliament on Tuesday will come into effect on 10 June.
The two substances are among 73 new psychoactive synthetic drugs that appeared on the market last year which are sold online and imitate the effects of more traditional illegal drugs.
In this case Benzo Fury mimics the effects of stimulant amphetamines such as speed while also having some ecstasy-like effects including experiencing sounds and colours more intensely. NBOMe is a psychedelic that imitates the effects of 1960s-style LSD.
The Home Office temporary class drug order has the effect of making it illegal to manufacture, import or supply the substances but not to possess them. Police and customs however do have a power to seize and confiscate temporary class drugs.
The Home Office drugs minister, Jeremy Browne, said: "This temporary class drug order will protect the public and give our independent experts time to prepare advice, while enabling law enforcement partners to target traffickers.
"Making drugs illegal is only part of the solution, however. Users of these substances need to understand that although they are described as 'legal highs', they are by no means safe," he said.
Prof Les Iversen, the home secretary's chief adviser on illicit drugs, publicly warned of the dangers of NBOMe last month, saying the novel LSD-style psychedelic sold as a "research chemical" was many more times powerful than its 1960s equivalent.
The chairman of the Advisory Council on the Misuse of Drugs said it was impossible to comprehend the microgram dosages involved because it was sold as a diluted solution dissolved on a piece of blotting paper.
European drug experts also confirm that this new psychoactive is far more potent than other similar phenethylamines that have emerged on the new drugs market. The European Monitoring Centre for Drugs and Drug Addiction (Emcdda) issued a public health warning about NBOMe substances in March after the first reports of non-fatal intoxications by doctors within Europe were made through its early warning system. Media reports from Australia and the US have linked it to deaths.
The second psychoactive substance to be affected is an amphetamine-style stimulant which has been found in a "legal high" branded as Benzo Fury, which can be bought from online shops for £10 each or £25 for three. They are sold as "research chemical pellets" and marked as not for human consumption. The brand name derives from the benzofuran ring in the substance's chemical structure.
A joint report by the Emcdda and Europol links one of its chemical ingredients, 5-IT, to 21 deaths in Britain, Sweden and Hungary between July and December last year. In some of these cases it may have been used in conjunction with other new substances and controlled drugs, including ecstasy. Calls in the UK for the drug to be banned followed the death of Alex Heriot, 19, at the Rockness music festival in Inverness last June. A postmortem in January identified ecstasy as the cause of his death.
The Home Office drug information website, Frank, describes Benzo Fury as commonly containing another chemical compound, 6-APB, and as a mild stimulant which may act like amphetamines such as speed and like ecstasy: "It can make you feel full of energy and experience colours and sounds more intensely. On the flip side it can cause panic attacks and leave people feeling confused," it adds.