A Royal Commission is a major ad-hoc formal public inquiry into a defined issue in some monarchies. They have been held in the United Kingdom, Australia, Canada, New Zealand, and Saudi Arabia. A Royal Commission is similar in function to a Commission of Enquiry (or Inquiry) found in other countries such as Ireland, South Africa, and Hong Kong. It has considerable powers, generally greater even than those of a judge but restricted to the terms of reference of the Commission. The Commission is created by the Head of State (the Sovereign, or his/her representative in the form of a Governor-General or Governor) on the advice of the Government and formally appointed by letters patent. In practice—unlike lesser forms of inquiry—once a Commission has started the government cannot stop it. Consequently, governments are usually very careful about framing the terms of reference and generally include in them a date by which the commission must finish.