Prime Minister's Office (Sri Lanka) the Parliament. The office of prime minister was formed in 1947 with D. S. Senanayake becoming the first Prime Minister of Ceylon. It consisted of a Secretary (Permanent Secretary) and an Assistant Secretary, who were officers of the Ceylon Civil Service, and a Private Secretary, along with clerical and support staff based at the Senate Building along with the Senate, Cabinet office and the Ministry of External Affairs and Defence. Since 1960 the prime minister's office has been based at Sirimathipaya Mansion on Sir Ernest de Silva Mawatha (formerly Flower Road), Colombo which was the former residence of philanthropist Sir
Acting prime minister is on vacation, or is in ill health. In the early 20th century, when travel by ship was still the norm, it was not uncommon for there to be an acting Prime Minister for months on end. The deputy Prime Minister is usually designated as the acting Prime Minister, although another senior member of the government may fill the role if both the Prime Minister and deputy Prime Minister are unavailable. An acting Prime Minister is required quite frequently – for instance, between 3 December 2007 and 23 February 2009 (during Kevin Rudd's first term), Julia Gillard acted as Prime