David Aaronovitch and a range of experts untangle the ideological threads that make up the 'Islamic State'.
Following its attacks in Paris, debate has raged about whether the so-called Islamic State is a political movement or a religious one.
But what if it's both, and more besides? David Aaronovitch calls on testimony from journalists, historians, political scientists and philosophers to explore the complex, sometimes conflicting elements that have shaped this organisation.
He examines its place in the long tradition of Apocalyptic anti-Westernism - a tradition that has also appeared in a European Christian context, in Japan, and elsewhere. David traces the role of senior figures from Saddam Hussein's regime in its creation and thinking, and asks whether avenging the invasion of Iraq has simply given IS its opportunity to prosper, or provides its guiding mission.
He explores the role of IS in the relationship between Sunni and Shia Islam, and its use of Islamic history in its worldview and its propaganda. And finally, David asks, how unusual is the Islamic State?
Producers: Phil Tinline and Wesley Stephenson.