Could the United States and Iran go to war?

The British Foreign Secretary has warned of the danger of Iran and the United States stumbling into a war by accident. And the signs are ominous: the US accelerated the deployment of an aircraft carrier and B52 bombers to the Persian Gulf and all non-essential staff are being withdrawn from the US Embassy in Baghdad. US National Security Adviser John Bolton said any attack by Iran on America or its allies would be met with what he called unrelenting force. So what's the risk of a war breaking out? David Aaronovitch is joined by: Ali Vaez of the International Crisis Group Kori Schake of the International Institute for Strategic Studies Aniseh Barissi Tabrizi of the Royal United Services Institute Robert Cooper, former EU diplomat. Barbara Leaf, former US diplomat and State Department official