Mesopotamia (modern day Iraq) had been ruled by the ailing Ottoman empire since the sixteenth century; yet the Anglo-Persian Oil Company had obtained exclusive rights to petroleum deposits throughout the Persian Empire, and had been contracted to supply the British Navy with oil. Britain was keen to protect the area around Abadan (modern day Iran) and had already sent forces there prior to declaring war on the Ottoman empire. Over the coming years the the British forces moved through the area, occupying cities such as Basra and Baghdad.
After the war local resentment towards the British grew. They had been led to believe that expulsion of the Ottoman rulers would lead to greater independence and autonomy for the area, when in fact it resulted instead in British occupation. The Iraq Revolt of 1920 was a direct consequence of this, and unrest in the middle east continues to this day.