Blue-green algae, which can be poisonous to humans and animals, formed on Lake Windermere in abundance as recent heatwaves coupled with masses of human effluent created the ideal conditions for its growth.

The sun is shining and in a scene that could have been plucked from an Arthur Ransome novel, dozens of children are swimming at one of the best bathing spots in Windermere.

Harmful algae blooms across the whole of England's largest lake could cause hundreds of thousands of fish to die, a zoologist has warned.

Matt Staniek said Windermere, in the Lake District, was "horrendous" and had turned a "horrible" green colour.

The blue-green blooms can make humans ill and can be fatal to animals.

SHOCKING pictures and videos have emerged showing the extent of blue-green algae blooms have taken over one of England's most famous lakes.

Prolonged high temperatures have seen harmful algae blooms spread across the "entirety" of England's largest lake, a campaigner has warned.

Council leaders have urged swimmers and dog-walkers to stay out of Lake Windermere because of the potentially toxic algae covering the water's surface - after experts warned that fish in the lake are choking to death and rivers and canals across 'Tinderbox Britain' turned green during the heatwave.

Windermere is dying and people swimming in it have been exposed to potentially toxic algal blooms, according to one passionate eco campaigner.

Lake Windermere, in Cumbria, has turned green because of toxic algae blooms worsened by last week’s heatwave. Local resident Matt Staniek’s petition to save Windermere from “sewage and an environmental catastrophe” has amassed over 130,000 signatures.

British rivers and lakes are being choked with algae thanks to the record-breaking heatwave that has scorched the UK.

Visitors to Windermere have been urged not to swim after sightings of large blooms of potentially dangerous blue-green algae in England’s largest lake.

“Some of our best loved and most iconic wildlife face a perilous future. We must act now to ensure that generations to come can marvel in the joys that our freshwater habitats can provide, from the magical sight of otters playing in our streams, the vibrant blue flash of kingfishers in flight, and the epic migration of the Atlantic salmon,” said a joint appeal by all of Britain’s major conservation organisations published last September.

A zoologist who is campaigning to prevent sewage being dumped in Lake Windemere has warned of an impeding environmental disaster after claiming his beloved dog fell seriously ill while swimming in England's largest lake.