A body was found in the water at Salford Quays after reports of a person having difficulty, amid high temperatures over the weekend.
Emergency services were called to the docks near Media City, in Greater Manchester, around 6.15pm on Saturday, with specialist search teams deployed to the scene.
Greater Manchester police said a body had been located, although at that time it had not yet recovered from the water.
Expert advice to stay cool: latest weather updates
Officers believe he is the person the emergency services were looking for, they said.
“His family has been informed by our officers and is receiving support at this extremely distressing time,” the police statement added.
Officers from the Salford fire team had been at the docks on Saturday to talk to members of the public about staying safe in warmer weather.
In the early hours of the day, crew rescued a young man who was having difficulty in the water.
They are among several emergency service teams that issue warnings about avoiding water as the heat increases.
“We want to remind people to never be tempted to cool off by swimming in open water, or to encourage your teammates to jump into reservoirs, rivers, canals or ponds (or any other open water),” they said in a statement. on Twitter.
Meanwhile, West Yorkshire police were called to Ardsley Reservoir on Saturday afternoon amid reports of a person in distress.
Emergency services continue to search the reservoir after a man was seen entering the water last night.
Read more on Sky News: A 16-year-old dies after swimming in the West Yorkshire Channel during the heat wave. Mother and daughter died when a tree rotted during the heat wave crushed her car
Earlier this week, a 24-year-old woman died after paddling on Conwy Morfa beach in North Wales, while last weekend a teenager died in an incident at a quarry in Wigan.
After the teenager’s death, the Northwest Ambulance Service shared a warning about “the hidden dangers of inviting water.”
The new health secretary has said new measures are being put in place, including additional working hours for ambulance teams as the UK faces its first national heat wave emergency.
Steve Barclay said additional support, which also includes more call handlers, will be launched on Monday and Tuesday.
Almost all of England is now covered by an amber heat warning from the Met Office, which will extend to Wales and the south of Scotland from Monday to Tuesday.
And temperatures will intensify, with the first red warning in the UK covering much of England, from London to Manchester and York, on Monday and Tuesday.
Temperatures could rise to 40ºC (104F) in London on Tuesday, as health officials warn of the dangers of extreme heat.