Who is to blame for the credit crunch?

According to media reports there are two suspects in the dock: the rocket scientists' (a.k.a. the financial mathematicians) who provided the information behind the market's decisions, or the greedy bankers who only thought about quick profits and their end-of-year bonuses. We talk to David Hand, Chris Rogers and John Coates to find out who is guilty. This podcast accompanies the article Is maths to blame?