Most people who died after taking legal highs had other drugs in their system, research shows

The research reignites debates about whether evidence regarding the harms of legal highs are accurate and sufficient

So-called 'Legal Highs' cannot be sold for human consumption so are often sold as incense, salts or plant food to circumvent the law (Rex)

Most people who die after taking legal highs had also taken another drug or alcohol at the time of their death, research has shown.

The research, by the Office for National Statistics, reignites longstanding debate surrounding legal highs and how safe they might be. It found that between 2004 and 2013, 60 per cent of people who died following consumption of a legal high had another drug or alcohol, or both, in their system at the time of their death.

The implication is therefore that it is unknown whether the legal highs were necessarily fatal, or whether death was related to the other drug or alcohol present. However, researchers say it is also possible that harder drugs users are deliberately mixing drugs and alcohol for the particular effects they induce and that this mix carries a high risk of fatality.

In response to the report, Liberal Democrat Home Affairs spokesperson Alistair Carmichael MP told The Independent: “The Psychoactive Substances Act is unworkable and lacks a clear evidence-base, something the Liberal Democrats have been saying from the start.

“Finally the Home Office is catching up by postponing the introduction of the Act but the Home Secretary should just admit she got it wrong and bin the legislation. I’m not counting on it though – the Conservatives have always put sounding tough ahead of politics.”

The Government had originally planned to ban legal highs from 6 April but recently revealed the plans would be shelved for at least a month following concerns that the Psychoactive Substances Act would not be enforceable for police.

The Act, which the Government has described as “landmark” legislation, to ban legal highs, which are often copycat versions of illegal substances slightly tweaked to evade anti-drugs laws but recreate much of the same effects.

The legislation attempts to close this loophole by prohibiting any substance which is capable of producing a psychoactive effect in humans. It is supplemented by a list of exemptions including alcohol, caffeine and nicotine. The legislation divided MPs.

Following prolonged debate at Westminster, amyl nitrate ("poppers") was not included in the Act on scientific advice that it does not directly affect the brain.