Eton College is being forced to spend £20,000 to keep its world famous Dorney Lake free of toxic blue green algae that poisoned two dogs.

The lake, which staged rowing events at the 2012 Olympics was badly hit by the toxic organism last month.

Two triathlons were affected as it was not safe for people to swim in, while Eton College is being forced to spent £20,000 to keep its world-famous Dorney Lake free of toxic blue-green algae that has already poisoned two dogs.wo pet dogs that dived into the water later needed emergency treatment at Alma Veterinary Hospital in Windsor.

The hospital subsequently put out a warning on social media saying: "We have treated two dogs in the last 24 hours for possible intoxication following swimming and drinking water from this area.

"We remind you that toxins produced by certain Blue Green Algae are extremely poisonous and may lead to death. There is no antidote."

This week a spokesman for Eton College said: "Blue Green Algae (BGA) was identified at Dorney Lake in mid-September. Hazard notices were immediately erected as warnings to visitors because BGA can release toxins that are harmful to both humans and their pets.

"The Environment Agency and an aquatic plant scientist were contacted for advice on the best way to eradicate the BGA. The measures taken were also informed by guidelines issued by the World Health Organisation and British Rowing."

In the end the weather helped.

The spokesman said: "The algae has now cleared, helped by the recent wind and rain.

"Dorney Lake is, of course, a rowing lake, not a lake for swimming and we do ask the public to keep dogs on leads and not allow them to enter the water.

"We have confirmation that the water is safe for humans, but as there may still be a small risk to any dogs which are not under proper control and which get into the water, we are retaining the warning notices until we get the final all-clear from the veterinary authority. "The College has placed an order for ultra sound technology to prevent future formation of BGA. This should mean that the problem is much less likely to occur.”