Dan Martin
BBC News, East Midlands
BBC
Part of the park was taped off after emergency services were called
A 16-year-old boy has died after getting into difficulty while swimming in a lake in Nottinghamshire.
Emergency services were called to Colwick Country Park when the boy went missing at 17:20 BST on Wednesday, Nottinghamshire Police said.
A police underwater search team and the fire service also responded, finding the boy's body just before 20:00.
Ch Insp David Mather said: "This is a tragic discovery and our thoughts are with this boy's family and friends at this incredibly difficult time."
"While work is now under way to understand how the boy came into difficulty, I would like to take this opportunity to highlight this case as a reminder of the devastating consequences of entering open water," Ch Insp Mather added.
"As in this tragic case, open water can have hidden dangers that can prove fatal and I would urge anyone who spends any time on or near open water to use this case as a devastating reminder of that."
The boy's death comes as parts of the UK are set to experience of the hottest day of the year so far.
Police said the death was not being treated as suspicious
Police confirmed the boy's death was not being treated as suspicious and said a file would be prepared for the coroner.
Group manager Tom Staples, of Nottinghamshire Fire and Rescue Service, said rescuers had worked tirelessly during the search.
He reinforced the message about the dangers of swimming in open water, adding: "We urge everyone to take care around lakes, rivers, and other natural bodies of water."
The country park is managed by Nottingham City Council.
City council executive member Sam Lux said: "This is an absolutely tragic incident and our hearts go out to the family and friends of the young person who has sadly died.
"As the current warm spell continues and as we approach the summer season we urge people to follow the guidance at Colwick park and other sites and not enter the water unless as part of properly supervised open water swimming sessions."