The conmen gained the trust of the elderly couple by offering condolences for their daughter and son-in-law. They had photograpahs in the room of both of them.
There were also photos of Harold's mum receiving a telegram from the Queen on her 100th birthday and a picture of the ship he served on during the Second World War - a mine sweeper that took part on D-Day.
The conmen then started doing a bit of work on the wall and said there was a problem with a bush near the house; the roots were affecting the foundations and urgently needed to be removed. They then insisted on being paid £3000 in cash.
More top news
A man standing trial accused of murdering two pensioners has been found hanging in his prison cell, police say.
Bees Number One is 'best in the league."
A union has said it is worried plans for Wandsworth and Richmond councils to merge may lead to job losses.