A man died while taking part in the Great North Swim, the organisers confirmed.
The man, 46, who has not been named, was taking part in a one-mile swim on Lake Windermere, Cumbria, when the alarm was raised by support staff at around 3pm yesterday.
Around 10,000 people were taking part in the three-day event which involves half-mile, one-mile and two-mile swims in groups of up to 300 people.
Many of the swimmers are amateurs raising money for charity.
A spokesman for the event said: "Nova International deeply regrets the tragic loss of life at the Great North Swim today and offer our deepest sympathy and condolences to the family and friends of the individual concerned.
"The police have been involved throughout and they have confirmed that there were no suspicious circumstances."
A spokesman for Cumbria Police said the alarm was raised by support staff, who travel alongside the swimmers in canoes, at around 3pm.
He confirmed the victim was a 46-year-old local man.Reuse content