Joke.

This made me laugh, on Annette's blog, so I nicked it:

Black Tarmac and Concrete are arguing in a bar.
"I'm harder than you! I built the M1" Said Concrete.
Black Tarmac retorts: "I'm harder than you, I built Heathrow's runways."
Just then the door bursts open and Black Tarmac and Concrete go quiet.
The barman notices this and asks them why.
"We might be hard.", says Concrete, "but he's a bloody cycle path."