Parliamentary Private Secretary to the Prime Minister Bonar Law's Parliamentary Private Secretary, J.C.C. Davidson acted in effect as his Chief of Staff. Margaret Thatcher's downfall from the Conservative Party leadership in 1990 is attributed by many to the actions of her Parliamentary Private Secretary, Peter Morrison, in failing accurately to count votes amongst Conservative backbenchers. Some Parliamentary Private Secretaries to the Prime Minister go on to hold higher office; Lord Dunglass served as Parliamentary Private Secretary under Neville Chamberlain and later went on to serve as Prime Minister in his own right. There can be multiple Parliamentary Private Secretaries to the Prime Minister at a given time.
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