Scammers posing as “water board” employees have been spotted in Surbiton, according to police.

The bogus callers are criminals who try to gain access to steal from people’s homes by posing as the employees of utilities companies.

People are advised not to keep large amounts of cash at home, to examine any caller’s identification cards and to be aware that the "water board" no longer exists.

Jon Lorimer, Thames Water’s security risk specialist, said: “The message is simple: If in doubt, keep them out.

"We send our engineers out with clear identification badges and if you still are not sure, phone us to confirm before letting them in."

Thames Water customers are also being encouraged to sign up to the doorstep password scheme, where they can set up a personal password to be given by any Thames Water employee that visits their property. 

Anyone who suspects a bogus caller can call the Thames Water helpline on 0800 316 9800 to verify their identity.