Enfield police are warning the elderly about distraction burglars operating in the borough.
Police are urging the public to be extra vigilant when unknown callers come to the door.
The warning comes after one resident in the borough let a man posing as an electricity board employee enter their home.
No items were taken but the man is believed to have searched the house.
The man is described as white male aged around 40 5ft 3ins tall and of medium build.
Detective Keith Kimberley, Enfield CID, said," This type of crime is not only unpleasant but very upsetting for the victim. The bogus caller will try to gain their trust. Once they have tricked their way into a property, they will steal whatever they can find.
"Bogus callers sometimes pretend to be on official business from respectable companies. In this case it was the electricity board but it might be another utility company or as a tradesman working on behalf of someone else.
"Residents can take some precautions to stop this happening to them. If you have a security chain, use it before opening the door to any unknown caller. Check their identification to make sure they are who they say they are. If they are a genuine caller, they will be happy to wait.
"I would urge anyone who thinks they might have fallen victim to a bogus caller to contact the police".
Rita Jones, 71, of Queen Elizabeth Drive, Southgate said she never opened the door to strangers.
She said: “I always look through my window before opening the door. You can get a lot of shifty people knocking. A lot of the time I don’t even answer it.”