The army served as presidential armies in Bengal, Bombay and Madras presidencies until April 1, 1895, when they were united into a single Indian army. It was subdivided into four commands for administrative convenience, namely Punjab (including the North West Frontier), Bengal, Madras (including Burma), and Bombay (including Sind, Quetta and Aden).
The British Indian Army was a vital supplement in both world wars to British armies in 1914–1918. 1.3 million Indian soldiers served with the Allies during World War I, killing or losing 74,187 Indian troops in combat. In 1915 Indian troops made a mutiny in Singapore. In exchange for its support the United Kingdom made promises of self-governance to the Indian National Congress but reneged on them after the war, after which the Indian Independence movement gained power.
Indian troops fought alongside the Allies in World War II. In 1939, British officials had no proposal to expand and train Indian forces comprising approximately 130,000 men whose mission was internal security and protection against a potential Soviet threat through Afghanistan. When the war progressed, the scale and position of the Indian Army grew significantly, and as soon as possible, troops were sent to battlefronts. The most serious problem was equipment shortage. Indian forces served in Burma, where five Indian divisions along with one British and three African divisions were engaged in 1944–45. In the Middle East even greater numbers served. In the war about 87,000 Indian soldiers died.
Four of the ten Gurkha regiments were transferred to the British Army in 1947 for Indian independence. The remainder of the British Indian Army was divided between India and Pakistan's newly formed nations. Throughout the partition era, the Punjab Boundary Force, which was formed to help police the Punjab, was dissolved. Delhi headquarters and East Punjab Command were created to administer the state.
The departure after independence of virtually all senior British officers, and their replacement by Indian officers, meant that many of the latter held acting ranks above their substantive ones. Each year in India, on 15 January, Army Day is observed in appreciation of Lieutenant General K. M. Cariappa 's appointment on 15 January 1949 of General Sir Francis Butcher, the last British commander-in - chief of India, as First Commander-in - chief of the Indian Army. With effect from 26 January 1950, the day India became a republic, all the officers of the active-duty Indian Army formerly holding the King's Commission were recommissioned and confirmed in their substantive rank.