Police are searching Hillingdon for a 15-year-old girl who has been missing for more than two weeks.
Amy Bowden, 15, from Chesham in Buckinghamshire, was last seen in Long Buckby, Northamptonshire, on Sunday, January 4.
Detective Chief Inspector Yvette Hitch, of Thames Valley Police, said: "We are becoming increasingly concerned for Amy's welfare and I appeal for anyone who may know of her whereabouts.
"We believe Amy may be in the Hillingdon area and anyone who sees a girl matching the description should contact the police immediately."
Amy is described as white, 5ft 1ins tall and of medium build. She has shoulder length brown hair, but may recently have dyed it blonde.
A spokesperson for the Metropolitan Police explained that colleagues from Thames Valley believe Amy may be in the borough.
* Contact Thames Valley on 08458 505 505 with any information.