One of the central challenges in modern British historiography is the reconciliation of narratives about the nature and meaning of the British Empire with older themes of class and hierarchy. The historiographical shift to empire and away from class since the 1980s and 1990s coincided with a fundamental shift in Britain's social structure and composition, which itself demands historical explanation. The history of the British honours system - an institution that has blended ideas of class hierarchy with meritocracy and service - can reveal much about social change in twentieth century Britain and its empire. Using a mixture of official and unofficial sources and organized chronologically, my dissertation charts the history of the honours system from the creation of the Order of the British Empire in 1917 to a major set of reforms at the end of the twentieth century and the beginning of the twenty-first. Honours were an active tool of policy and social distinction. Government decisions about who should receive honours and what honours they should receive reveal the importance of different kinds of service and the social class of the individual to be honored. Applied across the whole empire, the system had a double edge: it produced loyalty and kept different social groups in their place. The ever-presence of the institution means that it gives us a consistent benchmark across the twentieth century for what kinds of service was seen as most in need of recognition at different times by the state. The creation of the Order of the British Empire in 1917 opened up the honours system to non-elites, women and a much larger proportion of imperial subjects for the first time, and vastly expanded the number of people who received honours. I argue that change in the honours system during the twentieth century was not a simple matter of linear `democratization', as it is usually portrayed in the British media and by the modern British monarchy and government. Instead, it reflected different priorities at different times. In the empire, the state used honours to buy loyalty from subjects in exchange for social and cultural distinction; however, its symbolism was also appropriated positively and negatively by different groups to make political claims on or against the imperial state. Changes in who got what honours almost always had a specific purpose, and were often rapid. Initially conceived as a way of rewarding voluntary war work, in peacetime the Order of the British Empire was reworked to become an honour where the majority of awards went to paid central state servants. In the aftermath of the Second World War, in which government experts were well-rewarded with honours, politicians and bureaucrats made an effort to distribute honours more widely around the community. Teachers, health workers and other providers of local services benefitted from this change, as the honours system within Britain expanded almost in direct correlation to its shrinking global influence as the British Empire fragmented. At the end of the century, John Major's Conservative government made a deliberate decision to focus once again on voluntary service to the state. This uncontroversial shift in focus helped to bring together two of the functions of the modern British monarchy: its role since the nineteenth century as the official leader of the voluntary sector, and its function as the authenticator of public recognition through the honours system. This theoretically `classless' reform to the honours system reinforced existing divisions in British society by distinguishing between lower-ranked voluntary work and high-ranked professional, philanthropic and celebrity service. There was no clear-cut distinction between merit and hierarchy in the honours system. As a result, in periods of major social change in twentieth-century Britain, honours had an active role in reshaping social hierarchies in Britain and in parts of the empire/former empire. Honours obfuscated the meaning of distinction in modern Britain through the system's connection to the monarchy and its broad use as a political, imperial and social tool. A complicated and entangled combination of personality, status, merit, peer review and luck determined who received what honours. As a result, Britain's premier system for publicly recognizing service and distinguishing status could never fully differentiate between these two functions. In part this was because those who ran it did not desire to separate hierarchy from distinguished service, and because such separation was effectively impossible within existing frameworks. Citizens, subjects, interest groups and post-colonial governments used honours to challenge political and social structures, but it was difficult to break out of the fundamental framework in which honours gave distinction and status in exchange for a performance of loyalty to the Crown. The only escape was the complete rejection of the system, which was a rare choice except in certain parts of the former empire.