Harmful algae has been spotted in a popular Brent reservoir which is home to several sailing clubs.

British Waterways London has issued a warning after potentially toxic Blue-green algae (BGA) has been found in the Welsh Harp Reservoir reservoir, near Neasden. 

The toxins that can be produced can affect humans, pets and livestock. Reservoir users have been advised to avoid all contact with water that has a BGA scum on its surface, and also avoid very green water.

A British Waterways London spokesman said: "Immersion sports such as paddling, windsurfing, diving, swimming, water-skiing and canoeing carry a higher risk to human health and these should not be practiced where there is a scum or green water present.

"Such conditions can come and go quickly, which means that British Waterways cannot guarantee the suitability of the water for these activities. 

"Therefore it is your responsibility to check for scum or green water prior to any immersion activity."

Owners of pets and livestock have also been warned to keep their animals away from the water.

Anyone who comes into contact with BGA affected water should remove contaminated clothing and wash all exposed skin in clean water as soon as possible, particularly before eating or drinking.