Ambition, tyranny, war - just some of the themes Shakespeare deals with in Macbeth. Now, 400 years after the play was first performed, Melvyn Bragg looks at how the ideas it addresses continue to resonate in daily life. He discusses the many ways in which 'the Scottish play' has been referenced in popular culture, particularly in recent dramatisations concerning Tony Blair and his time in office, and examines how many of the play's characters have now become cultural archetypes.