Police have released a CCTV image of a man that they believe used the cards, after the robbery in Hayes, “in the hope that someone will recognise him”.
Officials put out the image today (Friday 11 November), though the crime occurred on Tuesday, 12 September.
Police said that it had been “quickly established that the woman's bank cards had been used in a couple of shops on Kingshill Avenue between midday and 2pm that same day”.
The Metropolitan Police Service released a statement, which said: “At approximately 11.20am on Tuesday, 12 September, a 79-year-old woman had her handbag stolen whilst walking along an alleyway off Grange Close. The suspect ran off in the direction of Park Lane.
“The woman was not injured. Her bag contained a number of items including her bank cards.
“The suspect is described as a black man, aged in his late teens to early 20s and 6ft in height. He was wearing a dark blue coat and dark coloured trousers.
Anyone with information is asked to contact the CID at Hillingdon via 101 or via Twitter @MetCC.