Police today warned clubbers to beware of a potentially deadly batch of Ecstasy after two people were taken seriously ill at one nightclub over the weekend.
A senior detective said it was known they had taken the drug and the batch of drugs was unaccounted for.
They were both in a critical condition in hospital after being taken ill at Fabric nightclub in Clerkenwell, central London, Scotland Yard said.
Detective Superintendent Adrian Usher said: "Over this last weekend we have had two incidents at this nightclub where two people are in a critical condition in hospital.
"We know they had taken Ecstasy and that this batch of drugs could be available in other locations across London.
"All drug taking involves an element of risk. Users need to be aware that a potentially fatal batch of Ecstasy is out there and understand the devastating effect it can have on their health. Drug dealers are only interested in making money so users can never be really sure what they are taking.
"I strongly advise people to be cautious and if they have purchased any Ecstasy recently to destroy it."
Anyone with information that could help police was asked to contact the CID at Islington on 020 7421 0196 or call police on 101.