David Cameron and Nick Clegg seem made for each other: Eton and Oxford meets Westminster School and Cambridge. But does the return of public school boys to the top of our politics say something worrying about the decline of social mobility in Britain? Andrew Neil goes on a journey from the Scottish council house he grew up in to the corridors of power to ask if we will ever again see a prime minister emerge from an ordinary background like his. In this provocative film Andrew seeks to find out why politicians from all parties appear to be drawn from an ever smaller social pool - and why it matters to us all.