Prime minister leader, the incoming leader will usually be referred as "prime minister-in-waiting". An example or this situation was in 2016 in the United Kingdom when Theresa May was elected leader of the Conservative Party while David Cameron was still prime minister. Ukraine's constitution (1996) lists the powers, functions and duties of the Prime Minister of Ukraine. 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, Margaret Thatcher was only ever appointed prime minister on "one" occasion, in 1979. She
Acting prime minister Acting prime minister An acting Prime Minister is a cabinet member (often in Westminster system countries) who is serving in the role of Prime Minister, whilst the individual who normally holds the position is unable to do so. The role is often performed by the Deputy Prime Minister (where that position exists), or by another senior Minister. The office is commonly used when the Prime Minister is absent from the territory of that nation, when the Prime Minister is in ill health or, on maternity leave. An acting Prime Minister should be distinguished from a caretaker Prime Minister, which refers