A man in his 60s is missing after five people were rescued when a rowing boat capsized on the river at Walton-on-Thames.
Crews from Surrey Fire and Rescue Service and the police attended the scene at Sunbury Lock, near Wheatleys Eyot, at about 08:51 BST on Friday.
Rescue teams appealed for members of the public to avoid the area while the search continued.
“Our crews are on site, working with the coastguard, Surrey Police and other agencies. Five individuals were rescued, and work is ongoing to locate a sixth,” a fire service spokesperson said.
Three of the five people rescued were taken to hospital for further checks, an ambulance service spokesperson said.
Surrey Police confirmed that of the six adults who had entered the water, “five of those people have since been accounted for”.
“Sadly, we believe a man in his 60s may still be in the river,” the force said in a statement.
“His relatives have been informed and are being kept updated.”
‘Very distressing’
Inquiries to establish the full circumstances of what happened are ongoing, they added.
Ch Insp Andy Jenkins said: “This is a very distressing time for all involved and we continue to support our partners in the search for the missing man.
“Our enquires to establish the exact circumstances of how the boat capsized remain underway but at this time we do not believe there to be any suspicious circumstances or third-party involvement.”
Monica Harding, MP for Esher and Walton, said: “This is an extremely distressing incident and my thoughts are with the family and all those impacted.”
The Environment Agency (EA) issues guidance on river conditions on the Thames, which are updated once a day by 11:00.
The warnings for the stretch of the river between Shepperton and Molesey locks were “red caution: strong stream” on Friday.
According to the agency, when red boards are displayed at the locks, users of all boats are advised not to navigate.
“The strong flows make it difficult and dangerous,” the guidance says.
An EA spokesperson said in general, and unconnected to Friday’s incident, that boat-owners should check river conditions, whether on boats or not.