The Fourth Plinth in Trafalgar Square is the competition in the art world that everyone is talking about. How do you choose between a car covered in pigeon droppings, wooden cruise missiles and a disabled pregnant nude? Ben Lewis interviews the artists including Sarah Lucas and Marc Quinn, critic Brian Sewell and the art world mandarins who are running it to try and answer the questions that are troubling him. The programme was originally shown in 2004.
