Visitors to Brent Reservoir are being warned not to dip their hands in the water which is currently polluted by a current outbreak of toxic algae.

The Canal & River Trust, which cares for the artificial lake, is urging people and their pets to avoid unnecessary contact with the water due to a bloom of blue-green algae.

The algae occur naturally in many inland freshwaters and warning signs have been placed around all affected areas.

Occasionally, blue-green algae ‘bloom’, colouring the water green, blue-green or greenish brown and sometimes causing paint-like or jelly-like scums.

Charity officers said the current outbreak is a natural occurrence and only in isolated pockets

Contact can be harmful to the skin, causing allergic reactions including itchy eyes, skin irritation and hay fever-like symptoms.

People are advised to wash exposed skin with clean water as soon as possible after contact with the toxic water.

Jon Guest, Canal & River Trust waterway manager, said: “Brent Reservoir is a really popular spot. We want people to continue to enjoy the lovely waterside setting, but just be aware that there’s a current outbreak of blue-green algae in the water.

“Blue-green algae is naturally occurring but it can be harmful to your skin. We’re asking people to be extra careful and if they or their pets come into contact with the affected water, they should wash all exposed skin with clean water as soon as possible, and especially before eating or drinking. If they are in any doubt about their welfare after contact with algae, they should seek medical advice.”

Brent Reservoir stretches from Wembley Park to Hendon. It is home to the Welsh Harp Sailing Club, Wembley Sailing Club, and the Sea Cadets,

The Trust – which cares for the reservoir and the Grand Union Canal which it feeds – is monitoring the level of the blue-green algae, which will die of naturally.

For more information about the waterways charity, including how to volunteer or donate, visit canalrivertrust.org.uk