The growth and reach of a group labelled a ‘terror force’ by President Trump. On 13 October President Trump announced new sanctions against Iran’s Islamic Revolutionary Guard Corp for supporting terrorism. But what is the Revolutionary Guard and what is its role in Iran and the Middle East? The group started as an army to protect the values of the Iranian revolution of 1979, but their role in fighting a long and brutal war with Iraq strengthened their military clout considerably. Today their forces work beyond their borders and have played a key role in the fight against so-called Islamic State. But they are no longer just an army, they run construction projects, run most of the telecommunications industry and even have a news agency. So how powerful is the Islamic Revolutionary Guard Corps? Presenter: Ruth Alexander Producers: Phoebe Keane and Jo Casserly (Photo: Iran's elite Revolutionary Guard special forces participating in military manoeuvers. Credit: Getty Images)