Gurinder Singh, who speaks only Punjabi, was found at a health centre in Southall, London. It is thought he wandered there after waiting hours for his uncle at a nearby bus stop.

Metropolitan Police and social services are trying to piece together the past life of Gurinder, who cannot name any relatives or friends but told police that he was deserted at the bus stop by a "white uncle".

"It's a real conundrum," Chief Inspector Keith Lunson said on Saturday. "It's a peculiar case. We are still struggling to get any information."

Police brought in a Punjabi interpreter who established that the boy had been in Britain for two or three years and had been living with his uncle. But he was unable to give his name or say where he lives.

"He says his parents are dead, and he came to Britain a couple of years ago to live with his uncle, who he says is white," Keith Lunson said.

Singh told the police that he had never been to school and was kept indoors watching television.

At first, Gurinder who is 5 ft tall, suggested he had travelled on a double-decker bus but then he saw a single-deck "bendy" bus and said that was his.

The boy has been put in social care for the weekend.

H S Gill, 61, librarian at the Gurdwara Sri Guru Singh Sabha near where the boy was found, said the community was baffled.

"Something like this has never happened here before and I've lived here 48 years," Gill said.