The Cock-o-meter, as seen in S10E10.
The Top Gear Cock-o-meter is an invention created by Jeremy Clarkson. It was first mentioned by Jeremy during The Cool Wall segment in Series 9, Episode 4 and made its appearance in Series 10, Episode 10.
The Cock-o-meter is a camera that takes a picture of the approaching car and driver, analyzes the picture and ranks it on a scale from 1 to 10, showing how much of a cock the car's driver is.
James May passed the Cock-o-meter in his Audi RS4 with a low score of 2, which Jeremy considers a good score. Then, Jeremy drives his Mercedes-Benz C63 AMG, passing the Cock-o-meter with a worse score of 7. When Richard Hammond drove past the Cock-o-meter in his BMW M3 E92, the needle went off the scale and jumped straight to "Danger". Laughing over Hammond's score with James, Jeremy stated that Hammond broke the machine.
The Cock-o-meter was mentioned in Top Gear: The Worst Car in the History of the World when James reviewed the Ford Escort RS Cosworth.