Newsnight - 21/04/2010

In-depth investigation and analysis of the stories behind the day's headlines with Jeremy Paxman. Diplomatic editor Mark Urban looks ahead to the foreign affairs leaders' debate where Trident is likely to be a key focus, with Brown and Cameron expected to attack Clegg over his proposals to scrap it. But is there a respectable defence debate to be had that replacing Trident with a similar system is too expensive and represents overkill? Comedian Danny Robins returns with the next instalment of Newsnight's Party Anthems - where he helps the three big parties set their manifesto promises to music to try to get their political messages across.