首相對內閣環繞有效討論、行政權力上支配立法議移嘅操控能力等結合效果，令英國首相嘅權力比作為一位行政主導首長。The relative impotence of Parliament to hold the Government of the day to account is often cited by the UK media as a justification for the vigour with which they question and challenge the Government.