The MGM Motor Company in Hatchet Lane, WInkfield, was raided by two men at 4.40pm on Sunday. They got away with a few hundred pounds.
No weapons were used and the shop assistant at the petrol station, also known as Brookside Garage, was not injured.
But owner Mike May, 63, was furious his member of staff has been put through the ordeal. He described the gang as 'scum.'
He added: "If I was running this country I would have them hung drawn and quartered - society is going downhill."
Mr May, who has run the garage since 1986, said he will be looking into ways to increase security at the site for staff.
Call 101 or Crimestoppers anonymously on 0800 555111.
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