Traffic lights in the Trafalgar Square area are reportedly not working following an alleged electrical explosion on nearby Cranbourn Street.
An eye-witness reported police and ambulances on the scene after a flash and a cloud of smoke. Blottr has been told by someone at the scene that a worker was electrocuted.
Pictures show an air ambulance landing in Trafalgar Square.
The lack of traffic lights is causing severe delays. Police are in attendance.
Photograph courtesy of @DanHowe.