Actually, had you bothered to watch to the end of that episode, the point they made was about HOW a car is driven and now WHAT car you drive.
They drove the Prius as fast as it would go, because someone who buys a Prius will do that and at that speed it would be less efficient than an M3 which is the "sports car" you mention.
And I agree with that point. If I flog my Civic, it'll return much smaller mileage than if I drive carefully and efficiently. So, again, Top Gear's point is proven in that, people aren't willing to think critically and live in a reality.
Exactly the point I took away from that test, it matters much more how you drive (calmly rather than aggressiely) than the car that you drive. This was even confirmed on mythbusters in their driving calm versus driving angry 'myth'.
They drove the Prius as fast as it would go, because someone who buys a Prius will do that and at that speed it would be less efficient than an M3 which is the "sports car" you mention.
And I agree with that point. If I flog my Civic, it'll return much smaller mileage than if I drive carefully and efficiently. So, again, Top Gear's point is proven in that, people aren't willing to think critically and live in a reality.