The author presents the prerequisites, progress, estimates and results of the reforms of the British army carried out by Edward Cardwell, the Secretary of State for War of the first liberal office of William Ewart Gladstone (1868 - 1874) from 1868 to 1872. The author notices that the Crimean (Eastern) war 1853 - 1856 was a powerful catalyst for the British army reforms. The ensuing "army discussion" of the 1850s and 1860s, the first place in which was assigned to the question of the system of purchasing officer ranks in the British army, even more significantly influenced the formation of the ideas of army reforms undertaken by Cardwell. The Secretary of State for War Eduard Cardwell has taken a number of rather progressive measures to reduce military spending on the maintenance of the army, ban on flogging, regulate the army reserve and abolish the purchase system of officer ranks for the effective development of the British army. The army reforms of Edward Cardwell, "the greatest of 19th century War Secretaries", were the beginning of the process of the gradual transformation of British forces into the effective and professional power of the British Empire. Contradictions related to the outcome of army reforms, attempts to abolish the results of reforms and return the army to the more suitable for aristocracy times of Wellington, according to the author, did not become a barrier to the continued existence of Edward Cardwell's army reforms even after the governmental change in 1874, when Cardwell left the post of State Secretary for War.