People who jump off bridges into the River Thames during hot weather are being told they risk injury or death. The warning has come from a police and Environment Agency team which is patrolling stretches of the river in Runnymede, Elmbridge and Spelthorne.
Police in north Surrey said there were recent reports of people jumping from bridges at Desborough Cut in Shepperton and Teddington Lock in west London.
Metal or glass and discarded shopping trolleys underwater are a threat.
'Real danger'
"Bridge jumping is a real concern to us," said River Thames Patrol Officer, Carl Walters.
"The water's depth and speed of current are difficult to gauge, there may be sharp objects hidden in the water and being struck by a boat is a real danger as boats cannot stop dead or manoeuvre quickly."
Mr Walters said people could enjoy the water during the summer months through supervised canoe, sailing or boat clubs.
Ch Insp Paul Smith added: "We have had reports in the past of bridge jumping at Staines and Walton bridges, and unfortunately there have been fatalities in previous years where swimmers have got into difficulty."
The Environment Agency said people should not attempt to swim across the Thames.