Constitutionalism is characterised by tensions and ambiguities. The Westminster constitutional framework is no different and, in the UK, these tensions are traditionally mitigated through informal institutions, underpinned by what Leslie Lipson called a ‘mutually beneficial bargain’. While the existing literature has pointed to a ‘transplant effect’ in which only the formal but not the informal institutions are transplanted, little is understood about the legacy effects of such transplants, how they are mediated by the presence, absence or modification of such a bargain, and the impact on the conduct and effectiveness of government. Using the case of Jamaica, this paper explores these issues by examining the constitutional tension between principles of responsible and representative government as they operate on the relationship between politics and civil service in the colonial and immediate post-colonial period. We argue that the constitutional legacy is one of a ‘mutually suspicious bargain’ between politicians and civil servants, which emerged under the era of colonial rule, but persisted into the post-colonial era, becoming, in the 1970s, a central flashpoint of constitutional conflict. As a result of this colonial legacy, there has been an unresolved tension in the operation of the Jamaican constitution regarding the appropriate balance between constitutional principles of responsibility.