The Supreme Court of Papua New Guinea has been the highest court of Papua New Guinea since 16 September 1975, replacing the pre-Independence Supreme Court (corresponding to the post-Independence National Court) and the overseas appellate tribunals from 1902 to 1975 of the High Court of Australia and the Judicial Committee of the Privy Council. Judges of the pre-Independence Supreme Court automatically became the first justices of the National Court and accordingly among the pool of judges that were available to be empanelled as a Supreme Court bench. Establishment and composition The Supreme Court was established as a superior court of record under Papua New Guinea's Constitution. The Chief Justice of Papua New Guinea, Deputy Chief Justice and the judges of the National Court (excluding acting judges) comprise the Court. Not separately constituted, the Supreme Court is an appellate committee or "full court" of the National Court, which is the superior-level trial court. Judges of the National Court form panels of the Supreme Court on an ad hoc basis to hear appeals from the National Court, appeals from assorted administrative tribunals, and to hear references in the Supreme Court's original jurisdiction. Reference jurisdiction and the separation of powers In the latter case the Court is, strictly speaking, not exercising a judicial function but rather, pursuant to the ruling of the Judicial Committee of the Privy Council in Attorney-General of Ontario v Attorney-General of Canada (Reference Appeal) [1912] AC 571, one of advising the executive branch of government, a jurisdiction expressly conferred on the Supreme Court by Papua New Guinea's Constitution. Other jurisdictions, notably the USA (federally, though not in all states) and Australia, eschew the reference function for their courts on the grounds that it violates the principle of the separation of powers as among the legislative, executive and judiciary; in Canada, it is held that the principle is inapplicable in a parliamentary democracy. The constitutional convention which deliberated on the drafting of Papua New Guinea's Constitution immediately prior to Independence took counsel from Canadian academics and the reference procedure was readily adopted. In Papua New Guinean jurisprudence, as in Australia, the formula "separation of powers" is frequently referred to. However, as in Australia (and unlike in the USA where the principle was enunciated and where the executive is not responsible to the legislature) it has a special limited application, being confined to describing the well-established convention of an independent judiciary,