A 15-year-old boy from Twickenham has been missing since December 3.
Police are appealing the public for assistance to trace Sam Jeffries, who was last seen at home around 8 am that day.
The 15-year-old had been in contact with his family, friends and police officers since, but that communication stopped in the last couple of days and police are increasingly concerned for his wellbeing.
Sam is described as around 5ft 11ins tall with a slim build. He has short brown hair and wears dental braces.
It is possible that when he left home he was wearing grey baggy jogging bottoms, a heavy grey hooded sweat top, white trainers and a red Burton ski jacket.
It is not believed he took a change of clothes.
Sam is known to frequent west London, Richmond and Hounslow particularly, and has possibly recently travelled via Waterloo.
Anyone who has seen Sam or who knows of his whereabouts is asked to call police in Richmond via 101.