This book, the first of a two volume study, provides an historical account of complaints against Metropolitan police officers between formation of the force in 1829 and codification of remedies for misconduct under the Police Act 1964. A complainant centred standpoint is developed to counteract the marginalization of the interests of victims, which is held to demonstrate that the drive for effective and efficient law enforcement has overshadowed the public interest in holding officers to account for misconduct. After officer accountability before the criminal courts diminished in the nineteenth century, missed opportunities to reform complaints procedures following commissions of inquiry in 1906-08, 1928 and 1960-62 are discussed. The second volume of the study, Combating Impunity: Complaints Against Metropolitan Police, 1964-2021, will examine the part played by complainants and civil society organisations in combating police impunity in the citizen oversight era.