From 1867, the Constitution of Canada was primarily contained in the British North America Act, 1867, and other British North America Acts, which were passed by the Parliament of the United Kingdom. Several Canadian prime ministers, starting with William Lyon Mackenzie King in 1927, had made attempts to domesticize the amending formula, but could not obtain agreement with the provincial governments as to how such a formula would work. Thus, even after the Statute of Westminster granted Canada and other Commonwealth nations full legislative independence in 1931, Canada requested that the British North America Act, 1867, be excluded from the laws that were now within Canada's complete control to amend; until 1949, the constitution could only be changed by a further act at Westminster. The British North America (No.2) Act, 1949, granted the Parliament of Canada limited power to amend the constitution in many areas of its own jurisdiction, without involvement of the United Kingdom. The constitution was amended in this manner five times: in 1952, 1965, 1974, and twice in 1975.