It might not be illegal, but that’s doesn’t mean it’s safe – that’s the stark warning from watchdogs as they work to tackle the worrying rise in the use of new psychoactive substances.

Because the drugs, commonly known as legal highs, have just been created legislation is not in place to bring them into line with other harmful narcotics.

The number of UK deaths linked to legal highs rose from 10 in 2009 to 68 in 2012, and only last month an inquest ruled that a 29-year-old builder died after using mephedrone, also known as meow meow, and a synthetic form of cocaine.

Herts County Council’s trading standards department is working with the police and district councils to tackle the national problem.

Recent surveys of young people have shown that 55 per cent had heard of legal highs and, of these, half said they had used or knew someone who had used them.

Councillor Richard Thake, County Hall’s cabinet member for community safety, said: “It is alarming that so many young people are being exposed to potential harm. We are determined to do everything we can to protect them.”

Det Supt Paul Maghie of Herts police said: “By taking new psychoactive substances you are taking serious risks.

“We do not know the exact contents of these substances but we know they can cause life-changing health conditions and in some cases, they can be fatal.”

You can get advice about the issues online at www.talktofrank.com. You can also call 0300 123 6600 or text 82111.