From another forum:
NATS STATEMENT
Just before 8am today a helicopter crashed in central London close to Vauxhall Bridge.
Earlier in the helicopter’s journey the pilot had been receiving an air traffic control service from NATS, although was not receiving a service at the time of the crash.
The incident will be subject to an investigation by the Air Accident Investigation Branch and NATS will assist any inquiry. Any further information should be from the AAIB or the emergency services.