Question: When did the country where Kolonnawa electoral district was located, leave the British Empire?

full_context: Document 1: Kolam Ayer Single Member Constituency: Kolam Ayer Single Member Constituency was a constituency in Singapore. It used to exist from 1976 to 1988, where Sidek bin Saniff was Member of Parliament. It merged part of Geylang West, Kallang and Potong Pasir.
Document 2: Senate of Ceylon: The Senate was the upper chamber of the parliament of Ceylon (now Sri Lanka) established in 1947 by the Soulbury Commission. The Senate was appointed and indirectly elected rather than directly elected. It was housed in the old Legislative Council building in Colombo Fort and met for the first time on 12 November 1947. The Senate was abolished on 2 October 1971 by the eighth amendment to the Soulbury Constitution, prior to the adoption of the new Republican Constitution of Sri Lanka on 22 May 1972. In 2010 there were proposals to reintroduce the Senate.
Document 3: Kohuwala: Kohuwala is a suburb in Colombo, Sri Lanka and is situated where the Colombo Piliyandala Road crosses Nugegoda Dehiwala Road. Hence it is connected to Nugegoda, Dehiwala and /Pamankada/Colombo and Boralesgamuwa/Piliyandala. Kohuwala is very close to Colombo South Teaching Hospital, Kalubowila. Kohuwala is inside the administration boundary of Dehiwala-Mount Lavinia Municipal Council.
Document 4: British Empire: Britain's remaining colonies in Africa, except for self-governing Southern Rhodesia, were all granted independence by 1968. British withdrawal from the southern and eastern parts of Africa was not a peaceful process. Kenyan independence was preceded by the eight-year Mau Mau Uprising. In Rhodesia, the 1965 Unilateral Declaration of Independence by the white minority resulted in a civil war that lasted until the Lancaster House Agreement of 1979, which set the terms for recognised independence in 1980, as the new nation of Zimbabwe.
Document 5: Colombo: Colombo (English: / kəˈlʌmboʊ /; Sinhalese: කොළඹ Kolamba, pronounced (ˈkəlɐmbɞ); Tamil: கொழும்பு, translit. Koḻumpu) is the commercial capital and largest city of Sri Lanka. According to the Brookings Institution, Colombo metropolitan area has a population of 5.6 million, and 752,993 in the city proper. It is the financial centre of the island and a popular tourist destination. It is located on the west coast of the island and adjacent to the Greater Colombo area which includes Sri Jayawardenepura Kotte, the legislative capital of Sri Lanka and Dehiwala - Mount Lavinia. Colombo is often referred to as the capital since Sri Jayawardenepura Kotte is within the urban area of, and a suburb of, Colombo. It is also the administrative capital of Western Province, Sri Lanka and the district capital of Colombo District. Colombo is a busy and vibrant place with a mixture of modern life and colonial buildings and ruins. It was the legislative capital of Sri Lanka until 1982.
Document 6: History of India: From 1920 leaders such as Mahatma Gandhi began highly popular mass movements to campaign against the British Raj using largely peaceful methods. The Gandhi-led independence movement opposed the British rule using non-violent methods like non-cooperation, civil disobedience and economic resistance. However, revolutionary activities against the British rule took place throughout the Indian subcontinent and some others adopted a militant approach like the Indian National Army that sought to overthrow British rule by armed struggle. The Government of India Act 1935 was a major success in this regard. All these movements succeeded in bringing independence to the new dominions of India and Pakistan on 15 August 1947.
Document 7: Avissawella Electoral District: Avissawella electoral district was an electoral district of Sri Lanka between August 1947 and February 1989. The district was named after the town of Avissawella in Colombo District, Western Province. The 1978 Constitution of Sri Lanka introduced the proportional representation electoral system for electing members of Parliament. The existing 160 mainly single-member electoral districts were replaced with 22 multi-member electoral districts. Avissawella electoral district was replaced by the Colombo multi-member electoral district at the 1989 general elections, the first under the PR system, though Avissawella continues to be a polling division of the multi-member electoral district.
Document 8: Second Sirimavo Bandaranaike cabinet: The Second Sirimavo Bandaranaike cabinet was the central government of Ceylon led by Prime Minister Sirimavo Bandaranaike between 1970 and 1977. It was formed in May 1970 after the parliamentary election and it ended in July 1977 after the opposition's victory in the parliamentary election. The second Sirimavo Bandaranaike cabinet saw Ceylon severing the last colonial ties with Britain as the country became a parliamentary republic in May 1972. The country was also renamed Sri Lanka.
Document 9: Beliatta Electoral District: Beliatta electoral district was an electoral district of Sri Lanka between August 1947 and February 1989. The district was named after the town of Beliatta in Hambantota District, Southern Province. The 1978 Constitution of Sri Lanka introduced the proportional representation electoral system for electing members of Parliament. The existing 160 mainly single-member electoral districts were replaced with 22 multi-member electoral districts. Beliatta electoral district was replaced by the Hambantota multi-member electoral district at the 1989 general elections, the first under the proportional representation system.
Document 10: Sri Lankan independence movement: The Sri Lankan independence movement was a peaceful political movement which aimed at achieving independence and self - rule for Sri Lanka, then Ceylon, from the British Empire. It was initiated around the turn of the 20th century and led mostly by the educated middle class. It succeeded when, on February 4, 1948, Ceylon was granted independence as the Dominion of Ceylon. Dominion status within the British Commonwealth was retained for the next 24 years until May 22, 1972 when it became a republic and was renamed the Republic of Sri Lanka.
Document 11: Kolonnawa Electoral District: Kolonnawa electoral district was an electoral district of Sri Lanka between March 1960 and February 1989. The district was named after the town of Kolonnawa in Colombo District, Western Province. The 1978 Constitution of Sri Lanka introduced the proportional representation electoral system for electing members of Parliament. The existing 160 mainly single-member electoral districts were replaced with 22 multi-member electoral districts. Kolonnawa electoral district was replaced by the Colombo multi-member electoral district at the 1989 general elections.
Document 12: Kadugannawa Electoral District: Kadugannawa electoral district was an electoral district of Sri Lanka between August 1947 and March 1960. The district was named after the town of Kadugannawa in Kandy District, Central Province. The 1978 Constitution of Sri Lanka introduced the proportional representation electoral system for electing members of Parliament. The existing 160 mainly single-member electoral districts were replaced with 22 multi-member electoral districts. Kadugannawa electoral district was replaced by the Kandy multi-member electoral district at the 1989 general elections, the first under the proportional representation system. The Kadugannawa electoral district was one of three multi-member constituencies, with two members, the others were Colombo Central and Balangoda.
Document 13: Dominion of Ceylon: Between 1948 and 1972, Ceylon was an independent country in the Commonwealth of Nations that shared a monarch with Australia, Canada, New Zealand and the United Kingdom, and certain other sovereign states. In 1948, the British Colony of Ceylon was granted independence as Ceylon. In 1972, the country became a republic within the Commonwealth, and its name was changed to Sri Lanka. It was an island country in South Asia, located about 31 kilometres (19.3 mi) off the southern coast of India.
Document 14: S. Mahinda: S. Mahinda arrived in Ceylon (now Sri Lanka) at a young age and was ordained as a Buddhist monk. Having learned the Sinhala language, he became a poet, creating several literary works inspiring patriotism among the Sinhalese and urging them to fight for their freedom during Sri Lankan Independence movement.. He is now considered a national hero of Sri Lanka and one among the greatest of Sinhalese poetry figures of all time.
Document 15: D. S. Senanayake: Don Stephen Senanayake (; ; 21 October 1883 – 22 March 1952) was a Sri Lankan statesmen. He was the first Prime Minister of Sri Lanka having emerged as the leader of the Sri Lankan independence movement that led to the establishment of self-rule in Sri Lanka. He is considered as the "Father of the Nation".
ground_truth: February 4, 1948
sub_queries: Kolonnawa >> country Answer: Sri Lanka
when did Sri Lanka leave the british empire Answer: February 4, 1948