High Speed rail - Tim Harford speaks to railway consultant Chris Stokes and Alison Munro from HS2 Ltd. He investigates the different measures of the rise in executive pay with Steve Tatton from Income Data Services and Sarah Wilson from research group Manifest. And resolves a four year-old bet on climate change between climate scientist James Annan and astrophysicist David Whitehouse and Wesley Stephenson looks behind the figures for youth unemployment in Spain.