Background Since its formation, the PAP was divided into two main factions: the
Fabian,
conservative, and
technocratic faction led by
Lee Kuan Yew, and the
revolutionary socialist and
Marxist faction 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 factions. Differences in their mass bases also encouraged such co-operation. During the early years, the left-wing faction mainly commanded support from the Chinese masses, rural people and trade unions, while support for Lee's faction 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. However, the two factions 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 faction as a means of assuring Singapore's future security and prosperity, while opposed by the left-wing faction 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 the PAP was widened by the
Hong Lim and Anson by-elections in 1961. Displeased with the PAP government's refusal to abolish the
Internal Security Council (ISC), refusal to back down the merger plan and refusal to release the remaining political detainees, the PAP left-wingers abandoned support for their own candidates in favour of
Ong Eng Guan (in
Hong Lim) and
David Marshall (in
Anson), which led to the PAP's defeat in the two by-elections. After the 1961 by-elections, the left-wing faction planned to oust Lee from the party but they worried that their actions would cause the British to hold up plans for Singapore's independence. As a result, the left-wingers had a meeting with
Lord Selkirk, the British Commissioner-General at
Eden Hall, which was later known as the "Eden Hall Tea Party". At the meeting, the left got assurance from Selkirk that Britain was committed to independence and would not intervene militarily to maintain control after the overthrow of Lee's government.
Formation On 20 July 1961, Lee Kuan Yew called an emergency meeting of the Legislative Assembly to vote on a
motion of confidence in the Government. Twenty-seven assemblymen voted for the government and twenty-four, including thirteen of PAP left-wingers, either abstained or voted against the motion of confidence. BS was officially inaugurated on 17 September 1962, with Lim Chin Siong as its secretary-general and Dr Lee Siew Choh as chairman. Its founding slogan was 'genuinely full internal self-government' through merger with Malaya • To eradicate colonialism and set up a united national independent state comprising the Federation of Malaya and Singapore • To establish a democratic Government of Malaya based on universal adult suffrage of all those who are born in or owe their allegiance to Malaya • To bring into being an economic system that will endure a prosperous, stable and just society • To mobilise all sections of the people for the building of a Malayan nation
Merger issue While BS didn't oppose the merger with Malaya, the party campaigned vigorously against the PAP government's merger terms with the Federation of Malaya. According to the merger terms agreed by the PAP government, Singapore would retain its autonomy in education and labour at the expense of the rights of Singapore citizens and seats in the new Federal Parliament. BS wanted Singapore citizens to automatically become Malayan citizens with proportional representation in the Federal Parliament. or that blank votes would be counted as Option A. The Referendum on Merger was held on 1 September 1962, and the results were 95.82% voted for Option A proposed by the PAP. As the blank votes are considered as Option A, BS's plan defeated. Among those detainees, half of them were BS central leaders. Operation Coldstore had substantially weakened the Barisan as most of its key personnel had been detained. According to Matthew Jones, "the Barisan never recovered from the combined effects of the outcome of the referendum result and the 'Coldstore' detentions." Jones also highlights that numerous Barisan leaders and members were bogged down with lawsuits and its followers were "demoralised". On 22 April 1963, Lee Siew Choh and remaining BS activists launched the "City Hall Battle". They marched from the BS's headquarter in Victoria Street to the steps of City Hall to protest the mass arrests in February and presented a petition to the Prime Minister in protest against the 'ill treatment' of the detainees.
Singapore's separation from Malaysia, expulsion of leaders and resignation of parliament seats BS had fought against the merger with Malaysia, however, upon the declaration of Singapore's independence from Malaysia in 1965, leaders of BS declined to recognise the independence of Singapore. Lee Siew Choh, chairman of BS attacked the independence obtained by Singapore, stating that it was not genuine and released public slogans of "Crush Malaysia", "Phony Independence", and "Boycott Parliament". On 15 January 1966, BS expelled two more of its leaders, Kow Kee Seng and Chio Cheng Thun. In October 1966, BS had all its remaining representatives in Parliament resign their seats and started what they called an extra-parliamentary struggle. BS returned to contest the
1972 general election and failed to win any seat with a clean sweep by the PAP. BS would fail to win any seats also in subsequent elections till 1984.
Merger into Workers' Party and dissolution In May 1988, BS was
de facto dissolved and merged into the
Workers' Party (WP) to strengthen the opposition and applied for dissolution. The application was rejected as BS's constitution required all its branches to agree to the dissolution but none were left. Hence, it has been left dormant since. In August 2025, around four decades after its shutdown, the
Ministry of Home Affairs (MHA) sought proof of BS' continued existence, along with that of 13 other political parties, as they had failed to comply with the
Foreign Interference (Countermeasures) Act 2021 (FICA). The Registrar of Societies (ROS) was ordered to officially deregister the parties if no proof was provided within three months. The party was officially deregistered on 4 December 2025. ==Communist allegations==