The bomb contained 25 to 30 lb (14 kg) of explosives and was set to be detonated by a timer.[4][5] It was left in a 1972 blue Austin 1300 GT four-door saloon car.[4] At 12:44 a man using an IRA codeword phoned the central London branch of the Samaritans charity.[4][5] The caller said there was a car bomb outside Harrods and another bomb inside Harrods, and gave the car's registration plate.[4][5] According to police, he did not give any other description of the car.[4]