The levels of “highly toxic” algae that can cause liver failure in dogs has started to rise in a lake.

Three Rivers District Council has warned people to keep their pets out of Batchworth Lake, with blue-green algae having started to become more apparent.

According to the British Veterinary Association, blue-green algae can contain toxins that can be harmful for animals if ingested, even in small quantities.

It said that dogs can swallow this algae by drinking water from an affected lake, river or pond or while licking their fur after going for a swim.

Symptoms including vomiting, diarrhoea and trouble breathing.

It could also cause live failure if ingested by pets, Three Rivers council warned.

It said water samples are currently being tested by experts at Batchworth Lake.

In a post on Facebook, the council said: “Please keep pets out of Batchworth Lake. An increase in the naturally occurring, but highly toxic, blue-green algae has become apparent and water samples are currently being tested by experts.

“The algae can cause vomiting and diarrhoea if swallowed or if it comes into contact with the skin. Ingestion may also cause liver failure in pets.”