In several parliamentary systems, notably the British, the Prime Minister is the head of the government, as opposed to the [Head of State]?. Prime Ministers can be found in both constitutional monarchies (as is the case in United Kingdom and Australia), and in republics, where the head of state is an official elected (as is the case with the president of India and Ireland) either by direct election or indirectly by parliament
This contrasts with a [Presidental system]?, where the President (or equivalent) is both the head of government and state.
Countries with systems of government modelled after the French, such as France, which has a mixture of the Presidental and Parliamentary system, also have Prime Ministers.
See also