Dog owners are being warned to keep their pooches out of a park’s lake after a poisonous algal bloom has developed there.

Epsom Council has issued the warning in relation to the Ewell Court Park lake.

It alerted the Environment Agency that the lake waters had developed a green sheen.

The agency has now conducted tests on the water, confirming the presence of blue green algae, Microcystis sp.

Two weeks ago the algae was responsible for the death of 2,000 fish in a pond in Wimbledon.

Blue green algae grows naturally in water.  When environmental conditions are favourable their numbers increase rapidly creating a 'bloom'.

A combination of warm temperatures, long summer days and high nutrient levels - sometimes caused by food dropped in the water by the public, such as bread fed to ducks - are factors in creating the conditions to cause such a bloom.

Blooms can last days, weeks or months, depending on weather conditions.

It is not possible to predict when or where blooms will occur or how long they will last.  Blooms run their course and dissipate naturally.

A spokesman said: "Epsom Council will undertake the treatment deemed appropriate to attempt to prevent any future bloom.

"The council is undertaking further tests.

"In the meantime we have placed warning notices around the lake advising people to keep out of the water and to prevent their dogs entering the water."