Deputy Prime Minister of Australia accepted the view put to him by McEwen that to commission a Liberal temporarily as Prime Minister would give that person an unfair advantage in the forthcoming party room ballot for the permanent leader. McEwen's appointment was in keeping with the previous occasion when the main non-Labor party was without a leader; Earle Page of the Country Party was interim Prime Minister between 7 and 26 April 1939—the period between Joseph Lyons' sudden death and the United Australia Party naming Robert Menzies his successor. Since 1968 only two Deputy Prime Ministers have gone on to become Prime Minister: Paul Keating
Prime Minister of the United Kingdom of government in the United Kingdom. The political position of Prime Minister was enhanced by the development of modern political parties, the introduction of mass communication (inexpensive newspapers, radio, television and the internet), and photography. By the start of the 20th century the modern premiership had emerged; the office had become the pre-eminent position in the constitutional hierarchy vis-à-vis the Sovereign, Parliament and Cabinet. Prior to 1902, the Prime Minister sometimes came from the House of Lords, provided that his government could form a majority in the Commons. However as the power of the aristocracy waned during the 19th century