Since the start of the US-Israel war on Iran, The Global Story listeners have been contacting us with questions: about the causes of the war, the legality of it, and how other countries are responding. As Gulf states get drawn further into the conflict, might they send military reinforcement? And if the Iranian regime were to fall, could islamist groups such as Isis seize an opportunity to claim more power?

In today’s episode, we answer all of these and more, with BBC world affairs editor, John Simpson.

Photo: A woman marches with an Iranian monarchy flag during a 'Freedom for Iran' protest in New York, New York, USA, 15 March 2026. Credit: Olga Fedorova/Shutterstock