A 16-year-old boy has died after getting into difficulty in Bray Lake, near Maidenhead, Berkshire.
Thames Valley Police said officers were called at 11.45am today and a body was located at just after 1.30pm.
He was pronounced dead at the scene.
Superintendent Michael Greenwood, the LPA Commander for Windsor and Maidenhead, said: “This is an absolute tragedy in which a young boy has died after getting into difficulty in the water of Bray Lake.
“The boy’s next of kin have been notified and are being offered support at this extremely difficult and traumatic time.
“My thoughts, and the thoughts of all of us at Thames Valley Police are with the boy’s family and his friends, and we would ask that their privacy is respected.”
Follow live updates on the UK heatwave in our live blog here
Royal Berkshire Fire and Rescue Service also attended the scene.
Earlier today police confirmed a 13-year-old also died from drowning in a river during the heatwave.
Northumbria Police confirmed the teenager had lost his life after 'getting into trouble' in the River Tyne near Ovingham, Northumberland.
A huge rescue operation was launched at around 4.15pm on Sunday involving Tyne & Wear Fire & Rescue Service, Northumberland Fire & Rescue Service, HM Coastguard and Mountain Rescue.
The Met Office has advised people to do "as little as possible" to avoid heat exhaustion in the blistering heat.
Instructions from meteorologist advised people Brits to avoid strenuous exercise and unnecessary trips.
The weather agency says there is now a 90 per cent chance that the UK record of 38.7C will be broken.