Police are appealing for witnesses after cash was stolen from a security box in Chafford Hundred on, Friday December 6.
A security guard from G4S was approached from behind while collecting cash from the Tesco Express in Fleming Road just after 10.40am. A five-figure sum of cash was stolen.
The driver, a man in his 50s, was shaken and received minor injuries.
The suspect was a white man who was wearing a balaclava and made off in a blue Fiat 500 which has since been recovered by officers.
Anyone with information is asked to contact the Serious and Organised Crime Team on 101 quoting incident 381 of 6 December, or you can call Crimestoppers anonymously on 0800 555 111.