Part of an office block being demolished beside Hounslow bus garage has collapsed, sending debris crashing to the ground, according to one witness.
Hounslow House, in London Road, just east of Hounslow High Street, is being demolished to make way for a possible housing development, dubbed Tesco tower.
A witness living in Aces Court, beside the long-empty office block, said he felt the earth shake as the building came down.
Bernard Zieja said it was a miracle no one had been injured by falling debris as about a third of the building collapsed in 'an uncontrolled manner' at about 4pm this afternoon.
He said he had been complaining about the demolition work for weeks as it had created huge amounts of dust blanketing neighbouring properties.
London Road is understood to have been closed at the junction with the High Street, and Hounslow bus station has been evacuated. Police, firefighters and paramedics are at the scene.