A man and woman found unconscious in Wiltshire were exposed to Novichok – the same nerve agent that poisoned ex-Russian spy Sergei Skripal, police say.
The couple, believed to be Charlie Rowley, 45, and Dawn Sturgess, 44, fell ill at a house in Amesbury on Saturday and remain in a critical condition.
Police say no-one else has presented with the same symptoms.
There was “nothing in their background” to suggest the pair were targeted, the Met Police said.
Home Secretary Sajid Javid has chaired a meeting of the government’s emergency Cobra committee to discuss the developments.