Real-time pollution warnings are needed at Lake Windermere after two people swimming there were taken to hospital last summer, campaigners have said. A seven-year-old boy developed life-threatening kidney failure following an E coli infection allegedly linked to him swimming in the lake. Windermere, in the Lake District in Cumbria, is one of the UK’s most popular open-water swimming destinations and attracts millions of visitors every year. In August last year, Claire and her family were kayaking in the lake when she noticed the water appeared murky, but she said she was reassured by the Environment Agency’s “excellent” bathing water classification. But hours later, her seven-year-old son became violently ill, suffering severe vomiting and rectal bleeding. He was admitted to hospital but his condition rapidly deteriorated, and after three days, he was transferred to a regional children’s hospital. The boy was diagnosed with haemolytic uraemic syndrome (HUS), a life-threatening condition which is one of the leading causes of sudden kidney failure in children. Four days later, he experienced hallucinations after toxins from the infection began affecting …