Prime Minister of Rhodesia held the post until the end of Federation on 31 December 1963. When Northern Rhodesia gained independence as Zambia on 24 October 1964, Southern Rhodesia began to refer to itself simply as "Rhodesia". Prime Minister Ian Smith's government issued a Unilateral Declaration of Independence from Britain in 1965, and he remained Prime Minister when the country was declared a republic in 1970. Under the Internal Settlement in 1979, after a long period of conflict, the country became known as Zimbabwe-Rhodesia, with Abel Muzorewa as its first black Prime Minister. None of these acts were recognised internationally, and under the Lancaster
Southern Rhodesia an Interpretation Bill to declare that the colony could be referred to as Rhodesia. The Bill received its third reading on 9 December 1964, and passed to the Governor for assent. However, no assent was granted to the Bill. Section 3 of the Southern Rhodesia (Annexation) Order 1923 provided that Southern Rhodesia "shall be known as the Colony of Southern Rhodesia" and the Southern Rhodesia (Constitution) Act 1961 and the Order-in-Council which followed it both referred to it as such. These were United Kingdom measures and it was outside the powers of Southern Rhodesian institutions to amend them. The Rhodesian