At first the resident, who was doing some ironing, didn't answer the call at her home in Bridgewood Road, Worcester Park when the suspect called on Wednesday, 10 December at 14:15hrs. But when she saw him peering through the letterbox, she opened the door.
The caller said he was a meter reader with Southern Electric and he was visiting because of a new government scheme to ensure customers are not overcharged.
Once inside, he asked the woman to see if the lights dimmed upstairs whilst he checked the meter downstairs. Moments later, he went upstairs and asked the woman to see if the lights dimmed downstairs.
The suspect left at around 14:50hrs saying that everything was fine and that she could expect a letter within a few days. He even gave the resident a quick kiss on the cheek as he left.
The victim then realised her property had been searched and police were called.
The suspect is described as black, aged about 30, 5ft 6in tall and of proportionate build. He had short, 'extremely curly' Afro hair. He was wearing dark clothing.
If you have any information to help, contact Sutton police station on 101. Alternatively, call Crimestoppers anonymously on 0800 555 111.
Det Con Mark Cooper, of Sutton CID, who is investigating this burglary, said: "Criminals like this are heartless because they prey on the elderly and vulnerable people who are naturally trusting and want to be helpful."
Police advice is that residents should always ask to see ID of callers from utility companies. If callers fail to produce it, residents should shut the caller out and call police on 999.