Legal highs are becoming more of a problem in Britain than hard drugs, a Home Office minister warned yesterday.

In an interview with the Standard, Norman Baker said dozens of young people were dying or risked horrific injuries after experimenting with new psychoactive substances.

“People think they are safe and legal when they may not be,” he said.

He warned that some legal highs — synthetic drugs which can be bought online and sometimes in shops — could be “more dangerous” than heroin or cocaine. “So I have initiated a review of so-called legal highs, which are a particular problem at the moment and becoming more serious than some of the traditional drugs in many ways,” he added.

Baker stressed that some legal highs could be harmless but added: “We just don’t know. We don’t know what the long-term consequences of these things are. They are more of a problem because we don’t know what they are until we have analysed them.”

“We have got a history of knowing what cocaine does or heroin does over decades and we are able to come up with some sort of policy.

“There is no such history of knowledge with some of these substances.”

In a wide-ranging interview, the LibDem minister also told how he had been briefed by MI5 chief Andrew Parker and accused political enemies of “maliciously” and wrongly claiming he would be denied access to sensitive papers because of his book which suggested scientist Dr David Kelly may have been murdered.

Campaigners are blaming more than 50 deaths a year on legal highs, including Adam Hunt, 18, of Southampton, and Hester Stewart, 21, of Brighton.

Baker said new substances were being developed “almost on a weekly basis” in laboratories across the world and were creating a “public health” problem in Britain. He said: “If they have temporarily come up with a chemical formula  - which means a drug is outside the Misuse of Drugs Act 1971, for the time being — until we get round to dealing with it — it then is a legal substance, at least temporarily.

“So then young people sometimes conclude wrongly that it’s safe because they think, not unreasonably in some ways, that if it was unsafe it would have been banned.

“So young people are sometimes less on their guard in terms of taking these new substances than they are for long-established substances like heroin, cocaine or cannabis.”