Tensions between powerful Middle East rivals Saudi Arabia and Iran were catapulted to new levels when drones set two Saudi Arabian oil refineries ablaze on 14 September, resulting in halving the Gulf kingdom’s oil output and cutting world crude oil supplies by over 5%. Yemen’s Houthi rebels claimed responsibility, but the US blamed Iran for the attacks, and will now deploy troops to the region, triggering fears of Saudi retaliation. Any escalation would be dangerous for the entire region. The drone strikes follow a recent pattern: oil tankers, infrastructure and transportation hubs have been attacked, with indications that Iran and its network are responsible. The US ‘maximum pressure’ policy has not halted Iran’s uranium development. President Rouhani said Iran would present a new Gulf peace initiative in the coming days. On 23 September Boris Johnson blamed Iran for attacks on Saudi Arabian oil facilities and declined to rule out military intervention or sanctions: see