PET OWNERS and swimmers in Oxfordshire are being warned about a toxic blue-green algae growing in water across the county due to the hot weather.

The Environment Agency has confirmed Croft Lake in Northmoor, near Witney, Baulking Lake in Faringdon, Ladygrove Lakes in Didcot, Jubilee Lake in Bicester and the Bicester Abingdon Marina have all tested positive for the substance which can kill animals and cause a rash in humans.

Banbury Cake:

Ladygrove Lakes, Didcot, in June   Picture: Environment Agency

Daryl Buck, a biodiversity officer for the agency, explained although the algae occurs naturally, when conditions are ideal for growth an 'algal bloom' can occur, producing toxins.

He said in extreme cases the organism would look like 'paint emulsion' but could also appear as if grass clippings were in the water and ranged in colour from a vivid blue-green to a more muddy shade.

Mr Buck added: "I'm sure there are more areas effected that have not been reported yet."

In June, hundreds of fish died at Ladygrove Lakes due to the algae starving the fish of oxygen.

An 'aerator' was used by the agency to increase oxygen levels in the lake.

Residents are asked to call 0800 807060 to report any algal blooms.