were comparatively backward-looking. This meant that trials such as the Experimental Mechanized Force of 1927–28 did not go as far as they might have. Operations One of the first post-war campaigns that the Army took part in was the Allied intervention in the Russian Civil War in 1919 to assist the "White Army" against the Communist Bolsheviks during their Civil War. Another was the Third Anglo-Afghan War (1918–19), fought in Afghanistan after the Emirate of Afghanistan invaded British India. The British Army was also maintaining occupation forces in the defeated Central Powers of World War I. In Weimar Germany, a British Army of the Rhine (BAOR) was established for the Allied occupation of the Rhineland. The BAOR would remain in existence until 1929 when British forces were withdrawn. Another British occupation force was based in Allied-occupied Constantinople in Turkey, and a number of British units fought against the Turkish National Movement during the Turkish War of Independence. A small British Military Mission was also advising the Polish Army during the Polish–Soviet War (1919–1921). The Army, throughout the inter-war period, also had to deal with quelling paramilitary organisations seeking the removal of the British. In Iraq, British forces put down the Iraqi revolt of 1920 against British rule in Mandatory Iraq. In British Somaliland, Diiriye Guure's men resumed their campaign against the British, a campaign that had first begun in 1900. The operations against him were prominent due to the newly formed RAF being instrumental in his defeat. The Army also took part in operations in Ireland against the IRA during the Anglo-Irish War. Both sides committed atrocities, some units becoming infamous, such as the paramilitary Black and Tans where many recruits were veterans of the First World War. The British Army was also supporting Indian Army operations in the North-West Frontier of British India against numerous tribes, known collectively as the Pathans, hostile to the British. The Army had been operating in the volatile North-West Frontier area since the mid-19th century. The last major uprising that the Army had to deal with before the start of the Second World War, was the uprising in Palestine that began in 1936. Rearmament and development By the mid-1930s, Nazi Germany was becoming increasingly aggressive and expansionist. Another war with Germany appeared certain. The Army was not properly prepared for such a war, lagging behind the technologically advanced and potentially much larger Heer of