Smash-and-grab raiders drove a van into the front of top-end jewellers Tiffany & Co before stealing valuables from the shop window.
Police were called at 2.56am on Friday to reports of a break-in at a jewellers in Sloane Street, west London.
Scotland Yard said a van was reported to have been driven into the front of the store before a number of people on mopeds stole items from the shop window.
The raiders then fled, leaving the van behind at the scene, the force added.
Pictures from the scene show a smashed window hanging in its frame with uniformed officers outside near a white van.
A Met spokeswoman said: “Police were called at 2.56am on Friday, April 26, to Sloane Street following reports of a smash-and-grab at a jewellers.
“A Transit van is reported to have driven into the shop front before a number of accompanying mopeds stole a quantity of items from the shop window.
“All those involved then fled. The Transit van was left at the scene.
“No arrests have been made. Inquiries continue.”
Anyone with any information should call police on 101 quoting reference CAD 0671/26 April.