Ben Wegener, 34, had pleaded guilty to robbery, dangerous driving and possession of an offensive weapon, criminal damage, and receiving stolen goods over the incident.
The car smashed through the glass front, narrowly missing customers who were shopping inside.
The three men, wearing motorcycle helmets and clad in black, got out of the car and began smashing glass display cases with a sledgehammer and hammer and stuffing their pockets and bags with jewellery and watches.
A member of the public outside the store can be seen attempting to stop the thieves by brandishing a piece of the store’s broken awning.
Smashing through a glass door, the suspects attempt to make their escape on foot but other members of the public give chase outside.
According to police, Wegener was pinned down and detained until police arrived several minutes later. The other two accomplices were able to escape.
The incident took place on 25 October last year. Wegener was sentenced at Isleworth Crown Court on Thursday.
Detective Constable Sam Weller, of the Central West Robbery Squad, said: “This was a reckless robbery committed in front of shoppers on a busy high street.
“It was sheer luck that no one was seriously injured when the vehicle smashed through the shop front and the shop owner and customers were threatened with serious violence when the robbers were inside.
“The raid was thwarted by members of the public who chased down and held Wegener as he tried to escape. This was a terrifying incident for the victims and everyone who witnessed it unfold and Wegener will now spend a significant period of time in jail.”