The cost of the large Mesopotamian garrison was thought excessive by almost all British politicians, but it was much less clear how to limit the occupying forces without loosening the imperial hold over at least part of the country. In August 1919 [Minister of War and Air Winston] Churchill had warned that the garrison of 25,000 British and 80,000 Indian troops would have to be drastically cut, and in November 1919 he suggested that British power could be more cheaply maintained if mechanized forces replaced some units of foot. He advised that the infantry garrison be reduced to a small force in a fortified camp near Baghdad, with blockhouses at other important points, while mechanized units-on land, on river and in the air-patrolled the rest of the country. This was the first of several similar schemes proposed by Churchill over the next two years. […]
But Churchill persisted in his attempts to find cheaper method of holding Mesopotamia. By early 1920 the garrison still included 14, 000 British troops, besides Indians, and expenditure was then running at about £18 million a year. Driven by this financial imperative, Churchill now began to think along more radical military lines. In mid-February he asked [Chief of the Air Staff Hugh] Trenchard whether he would be ‘prepared to take Mesopotamia on’: the bat an increase of five or six million pounds in the air force estimates and appointment of an Air Officer as Commander-in-Chief. Churchill believed that the country could be cheaply policed by aircraft armed with gas bombs, supported by as few as 4,000 British and 10,000 Indian troops; and he invited Trenchard to submit a scheme along those lines. Trenchard obliged, as he wanted to find an independent peacetime role to secure the future of his obliged, as he wanted to find an independent peacetime role to secure the future of his fledging service. The Air Staff drew up a plan by which Mesopotamia would be garrisoned by ten air force squadrons, mainly concentrated at Baghdad. Regular troops would be used only to guard air bases and perhaps for some limited co-operation with the bombers. As Trenchard pointed out, aircraft could strike swiftly into areas barely accessible to ground forces, could distribute propaganda and could obtain early intelligence of hostile masses. Churchill outlined his scheme to the House of Commons on 22 March.