POTENTIALLY toxic blue green algae has been found “at Millerground along with several other sites on Windermere”, a spokesperson for the Lake District National Park Authority has confirmed.

In addition, The Environment Agency said it was “actively monitoring” for blue green algae at Windermere (Low Wood and Rayrigg Meadow) and Coniston (Brown Howe).

An agency spokesperson added: “Due to the conditions we had last summer and throughout winter, we’ve received more reports of blue green algal blooms than usual over the last 12 months.”

In published guidance, the agency warned that blue green algae can produce toxins, adding: “These toxins can kill wild animals, livestock and pets. They can also harm people, producing rashes after skin contact and illnesses if swallowed.”

The agency spokesperson said: “Blue green algae naturally occurs in inland waters, such as our lakes in the Lake District. Blooms can form when their numbers become excessive.

“Once algal numbers are high, the bloom is likely to persist throughout the season, declining only on the onset of winter conditions.

“However, blooms form when the conditions are right, so they can form at any point throughout the year.”

They added: “It is difficult to tell whether this is a more persistent problem at this present time.”

Water affected by blue green algae or algal blooms may be green, blue-green, or greenish brown in colour. It can produce musty, earthy or grassy odours. Blooms can cause foaming on the shoreline, sometimes confused with sewage.

The Lake District National Park Authority said not all blue green algae is toxic but you can’t tell just by looking at it.

It advised anyone who spots blue green algae to keep themselves, children and pets away from the water, not to drink or swallow the water, and to call the Environment Agency on 0800 8070 60 to report the sighting.