Scotland Yard have issued CCTV images of two men dressed in suits, concealing handguns, who escaped with 43 rings, bracelets, necklaces and watches from the central London store in August last. They threatened staff at Graff’s with handguns, briefly seized a woman employee as a hostage, and fired warning shots as they made a getaway in a series of cars.

The extent of the heist had been kept secret but police have now disclosed that the items stolen had a retail value of $65 million (£40 million). Britain’s previous biggest diamond jewellery robbery is believed to be a £23 million raid, which also took place at Graff ’s, in 2003.

The two men, thought to be Londoners, arrived in a taxi at 4:40 p.m. on August 6 and were only in the New Bond Street jewellers for a matter of minutes. After being let in through the security doors both men produced handguns and threatened staff. They selected a total of 43 items and placed them into a bag before briefly seizing a woman employee hostage.