Royal prerogative in the United Kingdom

British passports and chivalric orders are regulated under the royal prerogative.

The royal prerogative is a body of customary authority, privilege, and immunity attached to the British monarch (or "sovereign"), recognised in the United Kingdom. The monarch is regarded internally as the absolute authority, or "sole prerogative", and the source of many of the executive powers of the British government.

Prerogative powers were formerly exercised by the monarch acting on his or her own initiative. Since the 19th century, by convention, the advice of the prime minister or the cabinet—who are then accountable to Parliament for the decision—has been required in order for the prerogative to be exercised. The monarch remains constitutionally empowered to exercise the royal prerogative against the advice of the prime minister or the cabinet, but in practice would likely only do so in emergencies or where existing precedent does not adequately apply to the circumstances in question.

Today, the royal prerogative is available in the conduct of the government of the United Kingdom, including foreign affairs, defence, and national security. The monarch has a significant constitutional weight in these and other matters, but limited freedom to act, because the exercise of the prerogative is conventionally in the hands of the prime minister and other ministers or other government officials.