After the British Labour Party suffered a crushing election defeat a year ago, the shell-shocked party took a dramatic turn to the left. New leader Jeremy Corbyn presented himself as the anti-austerity, anti-war antithesis of Tony Blair's new Labour. So, how is the Corbyn formula working? HARDtalk's Stephen Sackur speaks to Labour stalwart, shadow Foreign Secretary Hilary Benn and asks, does Labour present a credible alternative to the Cameron government?