Most prime ministers in parliamentary systems are not appointed for a specific term in office and in effect may remain in power through a number of elections and parliaments. For example, <answer>Margaret Thatcher</answer> was only ever appointed prime minister on one occasion, in 1979. She remained continuously in power until 1990, though she used the assembly of each House of Commons after a general election to reshuffle her cabinet.
Which prime minister was appointed only one time?
Margaret Thatcher