Michael Jones Jewellers was targeted for the fourth time in five years by a gang who smashed their way in with sledge-hammers on Tuesday morning.
They grabbed Rolex watches but fled when a security device discharged smoke in the shop.
One raider was then apprehended by a passer-by outside.
Stuart O'Grady, a director of the jewellers on High Street, said: "It was great to see. The British public are getting sick and tired on this going on."
The four raiders travelled down High Street on two mopeds as they targeted the jewellers at about 10:40 BST.
Mr O'Grady said: "These people are mindless - they rode down a pedestrianised area without any thought for the public.
"Two of them jumped off the mopeds with sledge-hammers and broke through the front door of the shop which is only unlocked for customers."
He added: "They grabbed a number of watches but we have a security device... which was deployed.
"It means you cannot see your hand in front of your face, that prompted them to run from the shop.
"Members of the public ripped the helmet off one of the men and the other was apprehended by three or four local people."
Mr O'Grady told how members of the public attempted to stop the other two members of the gang, who were waiting outside on mopeds, by throwing A-board signs at them.
"We want to thank everyone from the local community for their help - without doing what they did all four men would have got away," he said.
Mr O'Grady confirmed he and his staff were not threatened by the gang, but told of his frustration at the fourth raid in five years.
"We come to work to do a job but unfortunately the business we are in is classed as high risk," he said.
"We've had a loss of between £100,000 and £300,000 on the three previous occasions."
A 23-year-old London man has been charged with robbery in connection with the raid.
He was remanded in custody at Banbury Magistrates' Court, and is due to appear before Oxford Crown Court on 17 September.
A 21-year-old man from Essex was arrested on suspicion of robbery, and also of supplying drugs. A 25-year-old man from Banbury and 20-year-old man from London were also arrested on suspicion of robbery. All have been bailed until 21 October.
"Have-a-go heroes" who apprehended one robber and unmasked another in a bungled raid on a Banbury jewellers have been praised for their bravery.