A boy as young as five was enlisted by two men to steal from a charity shop in a distraction theft, police have said.
Scotland Yard released CCTV footage of a man instructing the boy to take the phone behind the till of a Cancer Research store in Wimbledon, south-west London, while an accomplice is said to have been distracting staff.
The boy is then seen lifting up his top and stuffing the phone down the front of his trousers.
The men, who detectives wish to trace, then left the store with the shop assistant's phone and with women's clothing which they did not pay for, the Metropolitan Police said.
Officers were called at around 3.45pm on October 11 to the store in High Street, Wimbledon, to reports of the theft.
Police described the first suspect as a large white man in his early 30s with a brown beard, while the second was a large white man in his late 20s.
Officers believe the boy is aged around five and they said he is white with short brown hair.
Pc Sue Clarke said: "We are keen to identify the two men in the CCTV footage who appear to use the child in their care to steal from those working in a Cancer Research shop. We would also urge anyone who witnessed the incident to contact us."
Anyone with information should call police on 101 or Crimestoppers anonymously on 0800 555 111.