Senior counter-terrorism officials now believe that the intelligence that led to the raid on a family house last Friday in a search for a chemical device about to be used to attack Britain was wrong, the Guardian has learned.

Counter-terrorism officials were under pressure last night after days of meticulous search of the house in east London failed to produce anything to link the two men they arrested to a chemical plot. But a senior police officer said they had been left with "no choice" but to force entry into the house because there was specific intelligence of a threat to public safety.