While the BNA Act eventually resulted in Canada having more autonomy than it had before, it was far from full independence from the United Kingdom. According to the Supreme Court of Canada, Canadian "sovereignty was acquired in the period between its separate signature of the "Treaty of Versailles" in 1919 and the "Statute of Westminster, 1931"" long after Confederation in 1867. Defence of British North America became a Canadian responsibility. Foreign policy remained in British hands, the Judicial Committee of the Privy Council remained Canada's highest court of appeal, and the constitution could be amended only in Britain. Gradually, Canada gained more autonomy, and in 1931, obtained almost full autonomy within the British Commonwealth with the "Statute of Westminster". Because the federal and provincial governments were unable to agree on a constitutional amending formula, this power remained with the British Parliament. In 1982, the constitution was patriated when Elizabeth II gave her royal assent to the "Canada Act 1982". The Constitution of Canada is made up of a number of codified acts and uncodified traditions; one of the principal documents is the "Constitution Act, 1982", which renamed the BNA Act 1867 to "Constitution Act, 1867".