Barisan Sosialis () was a political party in Singapore. It was formed on 29 July 1961 and officially registered on 13 August 1961 by left-wing members of the People's Action Party (PAP) who had been expelled from the PAP. The prominent founding members of the Barisan were Lee Siew Choh and Lim Chin Siong. It became the biggest opposition party in Singapore in the 1960s and the 1980s. The main objectives of the Barisan included eradicating colonialism, establishing a united independent and democratic Malayan nation comprising the Federation of Malaya and Singapore and introducing an economic system to promote prosperity and stability in society. The party was merged into the Worker's Party in 1988. Background Since its formation, the PAP was divided into the Lee Kuan Yew camp and the left-wing camp led by Lim Chin Siong. The common ground of anti-colonialism and independence of Singapore was the basis for the co-operation between the two camps. Differences in their mass bases also encouraged such co-operation. During the early years, the left-wing camp mainly commanded support from the Chinese masses, rural people and trade unions, while support for Lee Kuan Yew's camp was mainly found in the English-educated community. With the support of the working class, the PAP won the third-most seats in the 1955 election and formed the main opposition. In 1959, with the support of the trade unions, the PAP won the election and formed the Government under Lee Kuan Yew. However, the two camps were ideologically and politically different in nature. During its formative years, the left-wing members already showed their dissatisfaction with the policies carried out by Lee Kuan Yew and his failure to fulfill his promises to help secure the release of the left-wing political detainees. Finally, the contentious issue of merger with Malaysia triggered the split within the PAP. On 27 May 1961, Tunku Abdul Rahman, Prime Minister of the Federation of Malaya, suggested the creation of a new Malaysia state consisting of the Federation of Malaya, Singapore, Sarawak, North Borneo and Brunei. The reactions towards merger within the PAP were divided. The merger with Malaysia was supported by the Lee Kuan Yew camp as a means of assuring Singapore's future security and prosperity, while opposed by the left-wing camp as the merger was seen as an attempt to "wipe out the left-wing forces in Singapore" (Interview with Dr Lee Siew Choh). The rupture within