Robbers raided a luxury jewellery store in London's West End and escaped with £500,000 in watches under the noses of shocked shoppers, tourists and commuters.
The armed gang held off police during the heist at Watches of Switzerland in Oxford Street and officers had to retreat while they waited for backup from reinforcements with weapons.
The robbery happened in the middle of Thursday evening's rush hour.
According to witnesses, three masked robbers burst in to the shop and used hammers to prise watches off display boards. The stolen goods were swept into bags before the gang fled on foot before firearms officers reached the scene.
Witnesses described it as like something out of a film. On Twitter, one witness wrote: "Could hear the police coming. Thank God for rapid response."
Scotland Yard was due to issue an appeal for witnesses.