People are being warned to steer clear of a Superman style drug, which is believed to have caused the death of three men, and is now circulating in central Cambridgeshire.

Police are sending out the warning after receiving information that the drug is being sold locally in the Huntingdon area.

Dealers are selling it as ecstasy but police say it has been linked to recent deaths in Suffolk and the Midlands.

A Cambridgeshire Police spokesman said: “If you have taken illegal drugs or if you know someone who has become unwell after taking illegal drugs and needs urgent medical care call 999 and ask for the ambulance service.”

Anyone in possession of the drug is asked to surrender it to police in person or by calling 101.

The last week has seen the unexpected deaths of three men, two from Ipswich and one from Telford.

The men all appear to have taken a drug called PMA, phenoxymethylamphetamine, bearing the Superman logo that they bought.

It seems likely they thought it was ecstasy (MDMA).

PMA and its close relative PMMA are not new drugs; they were made in the 1950s and tested for beneficial mood effects then. However, they didn’t provide a clear positive effect so were discarded, though were made illegal under the UN conventions.

They have in the past few years re-emerged as a toxic surrogate for ecstasy. In this period they have been responsible for more than 100 deaths in the UK.

PMA/PMMA are significantly more toxic than MDMA for three reasons. First they are more potent, up to 10 times so. This means that a user who is typically safely using MDMA at a dose of 80mg per session will be taking the equivalent of 800mg of MDMA if they take 80mg of PMA.

Secondly, PMA works more slowly than MDMA so when users don’t get the expected effects of MDMA about 30 minutes after taking the drug they think they have been sold a weak lot and may take another dose to make up for this.

Then, when the effects of PMA kick in at around two hours, they have taken far too much.

Thirdly PMA and PMMA can cause a toxic reaction that elevates body temperature to a dangerous, and in some cases lethal level.

For drugs information and advice visit the Talk to Frank website or call the 24/7 National Drugs Helpline on 0800 77 66 00.