Doctors have warned legal high meow could be as dangerous as class A drugs.

Sussex's accident and emergency departments have seen a surge in teenagers overdosing on meow, or mephedrone, and consultants say they fear even more serious long-term effects are still to emerge.

Users of the drug have been seen overdosing, suffering heart palpitations, suffocating when their throats have swollen and suffering fits while high on the drug, which can be bought for as little as £5 a gram online.

Once revellers come down they can then suffer serious mental health problems including psychotic episodes and suicidal tendencies.

Paul Ransom, lead accident and emergency consultant at the Royal Sussex County Hospital in Brighton, and Princess Royal Hospital in Haywards Heath said he had seen an influx of young patients with serious medical problems caused by meow in the last few months.

Dr Ramsom said: “This is a real concern because we don't know exactly what long term or even medium term effects it could have, because it is so new.

“It does seem to have some terrible side effects in the short term.

“The problem is people are taking it again and again. It might be because it is cheap. It might be because it is seen as legal.

"It might be because the high doesn't last as long as other drugs and they need to take more and more.

“The patients we are seeing suffering problems from meow tend to be quite a bit younger than those suffering cocaine related problems.

"It is mainly people in the 16 to 25 year age group.

“That is a big concern for us that it is younger people so the side effects could be worse and they could be putting their lives at bigger risk.”