The British Army’s regular Mounted Infantry was arguably one of the most important innovations of the late Victorian and Edwardian armies. This thesis explores the regular Mounted Infantry model from its origins in extemporised infantry detachments overseas to its formal organisation as non-cavalry mounted troops before the First World War and juxtaposes its organisation and changing roles with its fractious relationship with the cavalry. Using four campaigns as case studies, the thesis provides a comparative assessment of the Mounted Infantry’s military effectiveness that culminated in it becoming the successful archetype for the British soldier in South Africa in the years 1901- 02. The Mounted Infantry’s uniqueness compared to other nations’ armies is considered and the thesis identifies how other armies satisfied the requirement for mobile firepower. The Mounted Infantry was abolished in 1913 prior to the First World War. The reasons influencing this decision are analysed and indicate that the Mounted Infantry’s abolition owed more to politics than lack of military utility. The thesis concludes that rather than an impecunious alternative to an inadequate cavalry, the Mounted Infantry paradigm satisfied a particular need borne out of colonial campaigning.