Two "cowardly" men armed with a kitchen knife and a 14-inch screwdriver robbed £750 from an off-licence while their accomplices acted as lookouts.
The four men then left Dream Food and Wine, in Groveley Road, Sunbury, and headed towards Feltham.
Despite the best efforts of the police dog unit, who carried out an extensive search of the area, the gang could not be found.
Leading the investigation, Detective Constable Steve Whitby said: "This clearly a very worrying incident where an innocent worker has been through a frightening experience, but fortunately no one was hurt during the robbery.
"Although serious incidents such as this are rare, when they do occur we take them very seriously and everything possible will be done to track these cowardly suspects down.
"I would urge anyone who saw anything or who believes they know the identity of those involved, to contact Surrey Police immediately."
The incident happened between 10.10pm and 10.25pm on Thursday, January 24, when two of the four black men entered the shop and threatened a 35-year-old worker, forcing him to hand over money from the till before fleeing the area with the other men.
All four men were wearing black jeans, black t-shirts, balaclavas and gloves. The two who carried out the robbery are about 5ft 6in tall.
Anyone who witnessed the incident or has any information should call Det Con Whitby at Staines CID on 0845 125 2222, quoting reference A/08/1985.
Alternatively call Crimestoppers anonymously on 0800 555 111.
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