The prospect of Turkish tanks rolling into northern Iraq – current oil exports: virtually zero – was enough to send crude prices soaring. So what would happen if bombs started dropping on Iran, the world’s fourth largest exporter?

The debate in Washington remains unresolved but the US has clearly made preparations for a potential strike on Iran’s nuclear programme. A wider attack on its oil facilities is highly unlikely, as is an Iranian response of cutting off supplies. Even if this occurred, Iran’s net exports of 2.5m barrels a day could, in theory, be covered by spare capacity in Saudi Arabia and the world’s 4bn barrels of commercial and strategic stocks.