An elderly woman was held hostage until her bungling captor fell asleep in her home.
A man posing as a gas meter reader falsely imprisoned the woman for two hours in Dunbar Avenue on Monday, February 13.
When she became suspicious, the man restrained her - causing her to fall to the floor.
But eventually the man fell asleep and the victim was able to get the front door and shout for help.
Her captor then woke up and fled.
The victim was left unharmed, but was shocked by the incident. None of her property was stolen.
Police are appealing for information to help them trace the man.
A spokeswoman for the Metropolitan Police said: “The man is described as black, aged 19 to 20, 5ft 5ins, goatee beard, London accent.
“He was wearing a dark hooded jacket, dark trousers and white grubby trainers.”
Anyone with information is asked to contact police on 101 or via Twitter on @MetCC.
You can also call Crimestoppers on 0800 555 111 if you do not want to give your name.