Stunned residents awoke to the sound of a World War II air raid siren after a huge fire broke out in south-east London Monday. Users of Twitter reporting hearing the unusual noise as firefighters tackled the blaze at a Greenwich warehouse. Air raid sirens were first heard in London in September 1939 and became virtually a daily part of life in the capital during the Blitz. The siren was used to encourage people to head for shelter. Around 70 firefighters were called to the scene of today's fire shortly before 3.30 A.M. London Fire Brigade said it was still trying to find out what was in the warehouse which was on fire, describing the 80m-long building as “well alight”. A man who called himself Dave told BBC London that there was thick smoke on the Old Kent Road, a couple of miles to the west of the fire. “You can't see your hand in front of your face,” he said. “It is like a smelly fog.” The fire brigade later said the source of the blaze was a chemical processing plant, but that the smoke was not thought to be harmful. It said that 60 firefighters remained at the scene and due to the heavy smoke it had received a number of calls from people across south-east London.
