Andrew Marr talks to the former British ambassador, Sherard Cowper-Coles, about the failures of Western policy in Afghanistan, and how diplomacy would have been a better option than the gun. In 2003 Baha Mousa was arrested by the British Army in Basra, in Iraq. Two days later he was dead. Richard Norton-Taylor sifts through all the evidence to bring the public inquiry into his death to the stage. David Pryce-Jones asks what motivates those who take up foreign causes, to the detriment of their own country, in Treason of the Heart. And the philosopher Angie Hobbs turns to the Greek Gods to untangle modern ideas of heroism and bravery.

Producer: Katy Hickman.