Neighbouring crane driver: 'Big fireball went up'
16 January 2013 Last updated at 13:14 GMT
Two people have been killed and nine injured when a helicopter crashed into a crane in central London in misty conditions.
Police said it appeared the helicopter had hit the crane on top a tower development at St George Wharf, beside the river Thames near Battersea.
The BBC spoke to a crane driver who was working on another crane nearby when the crash happened.