Ministers were told of explosion in 'legal highs'

Some 415 newly identified drugs, untested by medical science, are being sold to young people

The Government has failed to act quickly enough against the dangers of "legal highs", with mephedrone just one of hundreds of potentially dangerous substances sweeping across Europe, scientists said yesterday.

More than 400 new drugs have been identified in a report commissioned by the EU into the scale of the problem. The danger posed by legal synthesised drugs is far greater than people realise, according to Professor Fabrizio Schifano of the school of pharmacy, University of Hertfordshire.

The academic, who led the two-year Psychonaut study, said: "We have identified 415 psychoactive compounds, or combination of compounds which are not known in the medical literature, which means that the phenomenon is not just a little bit of mephedrone here or there."

He added: "Mephedrone is just the tip of the iceberg. The internet is driving this and the main concern is that these websites make it easy for young people to get hold of potentially dangerous drugs. We need to warn people of the dangers: legal does not mean safe."

Professor David Nutt, a former chairman of the Advisory Council on the Misuse of Drugs (ACMD), said the Government had "missed a trick" in failing to heed the warnings it made five years ago: "The Government's own Foresight committee contracted me and a few other people to look at the future of drugs back in 2004.

"We produced a report in 2005 and said the big problem is going to be the internet supply of synthetic drugs – we've got to do something about it. That was a very clear message from the report."

He claimed that officials ignored the ACMD's subsequent advice that a new category be created to cater for the new legal highs: "We did give this clear advice to at least be ready with a holding category, because, whatever you do to mephedrone, there will be a whole new slew of compounds.

"Believe me, the ACMD did try to get the Government to take this question seriously. We saw it coming, we predicted it, and it has arrived."

It is virtually impossible to police the problem, which could run into thousands of compounds, argued Professor Nutt. "The crime and justice side of things could get completely out of control. The police could spend their whole lives just arresting teenagers with mephedrone in their pockets."

Dubbed Britain's "favourite new drug" by the clubbing magazine Mixmag last month, mephedrone has become a popular replacement for ecstasy and cocaine. It is sold for around £10 a gram and is often described as "plant food". It has been linked with a series of deaths in the past few weeks, including Louis Wainwright, 18, and Nicholas Smith, 19, who died in Scunthorpe last Monday.

The deaths of the two teenagers ignited a row over the growing problem of copycat drugs that are subtly altered to be "legal" while having essentially the same properties, and risks, of the illegal drugs they imitate.

Police have confirmed that mephedrone caused the death of John Sterling Smith, 46, from Hove, East Sussex, last month. The drug has also been linked in the death of Steph Howard, 20, from Wigan, who also died last month.

The ACMD will meet to agree its recommendations on mephedrone and related chemical compounds next Monday. But, although ministers have pledged to take "immediate action", a ban is unlikely to become law until the summer.