A motorist died after attempts to talk him down from a major road bridge ended in failure on Sunday.
The drama happened on the Queen Elizabeth II bridge which links the M25 at Thurrock in Essex and Dartford in Kent.
Essex police said that the man, believed to be 42 and from Buckinghamshire, left his car on the bridge shortly after 11am.
A spokesman said: "He had pulled up in lane one before climbing over safety barriers on the bridge, standing on the other side and threatening to jump into the river.
"Police officers, including trained negotiators, spent several hours talking to the man trying to get him to come back over the barrier.
"At 3pm he walked to the apex of the bridge and plunged into the river."
He was recovered by lifeboat and taken to an ambulance waiting nearby before being transported to Darent Valley Hospital in Dartford, where he was pronounced dead.
The incident caused traffic delays. The spokesman said it was hoped to reopen the bridge once the man's car had been recovered.