This chapter explores the nature and significance of the constitutional convention of ministerial responsibility. It details the role and effectiveness of parliamentary scrutiny of the executive through questioning, debates and committees. One of the central constitutional relationships in the British constitution is that between the executive/government and the legislature. Parliament acts as a political and constitutional check on the government and this is crucial in the absence of a codified constitution constraining the activities of the executive. The convention of ministerial responsibility is, arguably, the most important convention in our uncodified constitution, as it purports to hold the government accountable to Parliament. The principle of collective responsibility can cause problems in the context of a coalition government composed of different political parties. Government ministers have to make executive and professional decisions for which they are responsible.