Swimmers and dog-walkers are urged to stay out of Lake Windermere as potentially toxic blue-green algae cover its surface.

According to the Environment Agency, blue-green algae is seen more often during periods of dry weather and its growth is exacerbated by nutrient pollution.

Scientists say that primary sources of nutrient pollution, include fertilisers, animal manure and sewage treatment plant discharges.

The Environment Agency (EA) North West has confirmed that a number of locations on Windermere are affected by the incident.

In a statement, South Lakeland District Council said: “The blooms pose a risk to human and animal health.

“Be prepared by checking the EA’s online map of known locations before you or your pet go swimming.”

Campaigners have launched a petition to save Windermere Lake from sewage – they claim sewage is being released for thousands of hours – these discharges have allegedly caused fish deaths.

Over the past decade, the EA has invested more than £700,000 in projects to improve water quality, improve ecology and better understand the Windermere catchment.