PC Plant, 41, from West Midlands Police, chased two robbers who leapt into a waiting car.
The driver drove straight at him and PC Plant instinctively jumped onto the bonnet and was catapulted onto the roof.
The green Mondeo weaved round oncoming cars for about a mile - going straight over a roundabout without stopping - as PC Plant lay on his front desperately clinging onto the roof.
Determined not to let them get away, PC Plant smashed the windscreen with his knee.
As the car slowed down, the three passengers jumped out of the car.
PC Plant chased the driver as the car crashed into a telegraph pole.
He cornered the driver and arrested him. One of the other robbers was also caught.
PC Plant says: "I was just determined to stop them and catch them - that's why I joined the police. If they weren't going to stop for me they weren't going to stop for anyone.
"I'm just a normal man but it's one of those things where you just act on instinct."