When Stockton swimmer Kate Sunley climbed out of the river after an open-water session at the town’s Preston Park last month, she found that the leg, which she had left on a jetty, was missing.

She suspected that the limb, nicknamed “Pogo”, had been thrown into the water by youths gathered nearby, according to a report in the Northern Echo.

Sunley knew that she would have to wait several weeks for a replacement to be made, but her plight came to the attention of diver Neil Richmond, 47, a British Sub Aqua Club regional coach, through social media.

He offered to help, and dived to the 5m riverbed in zero-visibility water that he described as “like cold coffee”.

Searching by touch he succeeded in finding the leg, tangled in litter including a mountain bike and a shopping trolley.

Sunley, who has been recognised as the world’s first disabled female “ice miler” by the International Ice Swimming Association, said it felt as if all her birthdays had come at once.

“Neil offered to help out of pure goodwill and I think it’s incredible – it has restored my faith in humanity,” she told the paper. “He’s a complete stranger who had the means to do something and did it, not for financial reward, but to help.”

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