This thesis is concerned with the origins and developments of a British-initiated force, known as "The Iraq Levies", which was raised during the Mesopotamian campaign of the First World War. This is a subject which had previously received very little rigorous historical study. The Force began with some forty mounted Arab scouts, recruited from Zubair in southern Mesopotamia by the Field Intelligence unit of the Imperial Expeditionary Force (I.E.F. 'D') in July 1915. By May 1922, the Force had expanded to approximately 6,000 officers and men, as against a planned 7,500 at the Cairo Conference. A survey of the performance and military background of several British officers who served with the Levies, was considered worthy of study. Mostly they came from the Indian Army, and thus were experienced in what may be described as "political soldiering" - an invaluable qualification for their service in Iraq. It was felt important that the different ethnic backgrounds and political aspirations, as well as religious loyalties represented in the ranks of the Levies required investigation to assist in an understanding of their motivation and service. Without a detailed review of these factors, it would be difficult to comprehend how a force which could be considered to owe its allegiance to its pay-masters, could undertake the task of internal security in so volatile a region as that of Iraq, especially during and after the First World War. When its political problems, both internal and external, had to be resolved by the British government which became the mandatory power. This thesis ends with the achievement of Iraq's independence in 1932. The Levies, however, were not finally disbanded until May 1955. That final section of their history was not to be without drama and incident; but it awaits the attention of another student who is interested in the nature and evolution of British Imperial Forces in the Middle East. Their day has now ended, but this thesis hopes to illuminate a little of their history and significance.