A powerful double-barrelled shotgun was stolen after its owner left it "unattended" on a London street, police said.
Detectives are hunting for the Beretta EELL 12-gauge weapon stolen after being unloaded from a car in Fulham at around 7.30pm on Thursday.
Scotland Yard said that a man picked up the gun in its brown leather case while it was "unattended" outside a building in Langthorne Street and "made enquiries as to who the owner was" before disappearing with it.
Detective Sergeant Matt Besch said: "We would urge this person who has found the shotgun, to contact us so its recovery can be arranged, and we can ensure it does not fall into the wrong hands."
The gun is described as having a dark brown stock with "rose-style" engraving on the handle, and its wooden parts are said to look "tatty" from not having been oiled recently.