FEARS that Islamic terror suspects were preparing a bomb laced with cyanide prompted Friday’s counter-terrorist operation in east London in which an unarmed man was shot by police.

Scotland Yard sources said that the “specific intelligence” which had led to the raid suggested that a single bomb overlaid with cyanide was being prepared at the address in Forest Gate.

MI5 had been told last month by an informant that two Islamic men who were already well known to the security services were preparing a device.

The informant, an acquaintance of the suspects, is said to have told MI5 that he had overheard them talking about how they were going to fill a pouch or pouches made of cloth with explosives.

A later assessment concluded that the device would be laced with the chemical cyanide, which would be sprayed in a toxic cloud over a wide area after exploding.

The threat was regarded as so serious that Dame Eliza Manningham-Buller, director-general of MI5, personally informed Tony Blair and John Reid, the home secretary, in advance of the raid.

Sources said an emergency meeting of Cobra, the top level government committee that deals with terrorist emergencies, was immediately convened to monitor the threat.

The intelligence on cyanide explains the presence during the raid of officials from the health protection agency.

At normal temperatures cyanide is a colourless gas or a brown yellow liquid. Exposure to high concentrations is usually fatal.

Scotland Yard said yesterday that despite intensive searches of the terraced house in Lansdown Road, Forest Gate, nothing of substance had been found, raising the suspicion that at least some of the intelligence that led to the raid was inaccurate.

A 23-year-old man, named locally as Abdul Kahar Kalam, was shot in the shoulder when a Scotland Yard marksman fired a single shot during the pre-dawn operation.

According to his solicitor, Kate Roxburgh, police did not issue a warning before he was shot as he stumbled onto the staircase in his pyjamas.

“He wasn’t asked to freeze, given any warning and didn’t know the people in his house were police officers until after he was shot,” she said. “He is lucky still to be alive.”

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