In the early hours of Saturday, Feb 2, 1963, hundreds of armed policemen set off from the Special Branch headquarters in Robinson Road and outlying police stations in a major islandwide operation.
Codenamed Operation Coldstore, they visited homes and offices of leftist leaders and trade unionists, detaining 107 that day.
The swoop, The Sunday Times reported the next day, was "aimed at preventing subversives from establishing a 'Communist Cuba' in Singapore and mounting violence just before Malaysia".
These arrests shattered the underground communist network throughout the island.
The threat lingered, but as it faded over the years, many of those detained were released and went on to lead quiet lives.
In recent years, some have sought to give their version of events. As the 50th anniversary of Coldstore approached, several former detainees and academics began working on a book on their perspective on the detentions.
In The 1963 Operation Coldstore In Singapore: Commemorating 50 Years, launched in late 2013, they argued that the arrests were politically motivated against the leftist opposition and overstated the security threat.
Other articles and commentaries have also surfaced. Former Coldstore detainee Poh Soo Kai, a Barisan assistant secretary-general, argued last December that the purpose of Coldstore "was to eliminate Lim Chin Siong and the Barisan Sosialis from the 1963 general election".
In a feisty response to Dr Poh, the Government reiterated its position that Barisan was the main vehicle of the Communist United Front (CUF). The Barisan was formed by left-wing members who broke away from the People's Action Party (PAP) in 1961.
A new book launched this month also challenges several of these "revisionist" accounts of the communist threat head-on.
In "Original Sin"? Revising The Revisionist Critique Of The 1963 Operation Coldstore In Singapore, historian Kumar Ramakrishna rebuts three broad claims made by those who argue Coldstore was politically motivated.
These are: that the communist threat had been neutralised by the 1960s, that Barisan Sosialis leader Lim Chin Siong was not a communist or a security threat, and that Coldstore had been mounted to get rid of the progressive left.
Insight looks at these arguments and the rebuttals, and what shape the debate might take.
Was there a credible communist threat in the 1960s?
THE Communist Party of Malaya (CPM) was formed in 1930 and began establishing links with labour unions in Singapore and Malaya. During the Japanese invasion and occupation from 1941 to 1945, it was a key armed resistance force. But after the CPM launched an armed insurgency in 1948, the Malayan government declared an Emergency, arresting leading CPM members and declaring the CPM illegal.
The CPM in Malaya was driven underground. But it embarked on a brutal campaign that took thousands of lives and drew a backlash from the authorities.
The failure of its jungle war in Malaya revived interest in urban struggle in Singapore, and official accounts show the CPM reviving its "united front" strategy of subverting trade unions and student bodies, as well as political parties like the PAP, with the long-term goal of a communist Singapore, and then Malaya.
However, Dr Poh argued that the CPM was "a decimated force in Singapore by the 1950s", largely due to the Malayan Emergency, and as a result wielded little influence over everyday events in Singapore.
Several historians described as "revisionists" have also said the scale of the communist threat was exaggerated by the authorities.
Historian Thum Ping Tjin went a step further to say that the "historiography is clear on the lack of evidence of a communist threat".
They argue that much of the left-wing radicalism - whether of students or trade unions - in that period was uncoordinated, and was more reflective of the general anti-colonial mood at the time, rather than the subversive hand of communism.
Such a view is problematic, says Associate Professor Kumar, who is head of policy studies at the S. Rajaratnam School of International Studies. He points out that the revisionists have ignored the writings of leading CPM members like Chin Peng and Fong Chong Pik, who have acknowledged their role in the CUF.
In his book, Dr Kumar argues that the communists did not resort to open, armed revolution in Singapore not out of principle, but because they could not match the strength of the British.
Instead, they adopted the CUF strategy of "peaceful struggle" by infiltrating legal organisations such as student unions and trade unions, gaining significant ground in Singapore in the 1950s.
The goal, in the words of long-time CPM secretary-general Chin Peng, was to fan hatred towards the government and undermine public order by "skilful exploitation of controversial issues and public grievances, genuine or otherwise".
These include orchestrating riots against national service in 1954, and the Hock Lee bus riots of May 1955, which saw four dead and 31 injured.
Retaliatory strikes by student and trade unions in 1956 to protest against the Lim Yew Hock government's crackdown on CUF organisations also culminated in riots that led to 13 deaths and 123 being injured. The widespread violence saw two schools burned down, 70 cars destroyed and two police stations damaged.
This led to the banning of both the Singapore Factory and Shop Workers' Union and its student equivalent, the Singapore Chinese Middle School Students' Union, and the CPM changing tack to focus on penetrating grassroots organisations and the PAP, which was founded in 1954.
The communists then attempted to seize control of the PAP in 1957, when they won six of the 12 seats on the central executive committee. They also withdrew their support in the Hong Lim and Anson by-elections in 1961, both of which the PAP lost.
These attempts, Dr Kumar says, showed a CUF determined to capture power in Singapore through constitutional means after violence failed: first with non-communists like Mr Lee Kuan Yew as cover, and then later through the Barisan, having hollowed out the PAP through defections when the marriage of convenience became untenable.
This series of events, he adds, demonstrated the CUF's nature as a "resilient, clandestine subversive organisation"."The CUF was all too real an entity in Singapore from the 1940s to the 1960s."
Associate Professor Bilveer Singh, who has written a book charting the history of communism in Malaya and Singapore, also points out that the communist threat here continued even after Operation Coldstore, with 22 incidents of arson and 11 bombings between 1969 and 1976.
He wrote in Quest For Political Power - Communist Subversion And Militancy In Singapore: "The various plots and acts of violence should debunk the notion that Singapore was not a military target, and refute claims that the communists did not do very much in Singapore."
Who was Lim Chin Siong?
A KEY issue in recent attempts to question the legitimacy of Coldstore is whether top Barisan leader Lim Chin Siong was a communist.
An influential trade-union organiser and co-founder of the PAP, Mr Lim was elected to the Legislative Assembly in 1955 as a member for Bukit Timah at the age of 22.
The party brought together pro-communist trade unionists, who needed a respectable, non-communist party leadership, and the English-educated group, which needed the mass support base offered by the unions.
Mr Lim's role in the Chinese middle-school disturbances in 1956 saw him detained that year, and he was released in 1959. He was also among the key Barisan leaders detained in Coldstore.
But former detainees and revisionists say he was not a CPM member, and if communism was the spectre upon which Coldstore was launched, then Lim Chin Siong was its chief victim.
Fellow detainee Lim Hock Siew said Mr Lim was a leftist who fought for the exploited and against the British, but broke with Mr Lee because he felt the terms of merger with Malaya were unfair.
Dr Poh cited then British deputy commissioner Philip Moore, who had said in 1962 that "while we accept that Lim Chin Siong is a communist, there is no evidence he is receiving orders from the CPM, Peking or Moscow. Our impression is that Lim is working very much on his own".
Dr Poh also cited the British commissioner in Singapore, Lord Selkirk, as saying Mr Lee was "quite clearly attracted by the prospect of wiping out his main political opposition before the next Singapore elections".
Historian Hong Lysa also argued that if colonial records do contain any concrete evidence that Lim Chin Siong was a communist, "that would have been brought to light from the start, and not fester as a thorn in the PAP's flesh even 50 years later".
The establishment, she added, was "perpetuating Lim Chin Siong as communist bogey".
However, many other academics and officials reject these claims, citing ample evidence in the British archives to show that Mr Lim was a CPM member.
Dr Kumar was also granted access to several classified files from the Internal Security Department's archives, and draws on them to show that Mr Lim's career in the CUF "appeared to have been planned and charted from the start by the CPM".
From his affiliation at age 15 in the Malayan New Democratic Youth League, a communist-linked group, to his joining the CPM-linked Anti-British League (ABL), Mr Lim appears to have been captivated by communist ideology from an early age.
Other evidence of Mr Lim's CPM ties includes known associations with ABL subordinates, some of whom were caught by the police and admitted to having been inducted into the ABL by him.
Associate Professor Albert Lau of the National University of Singapore history department notes that available accounts from former ABL members show that Mr Lim was a key ABL and CUF leader and also a CPM member.
Senior CPM leaders have also revealed - whether under questioning by the police, or in their memoirs - that he was a member of their circle.
This included Fong Chong Pik, the highest CPM authority in Singapore who was known as "the Plen", calling him "a person with whom I have had a special acquaintance" .
The evidence is corroborated by two CPM leaders in Malaya, who cited him as a member deployed in open-front activities.
More instructively, Dr Kumar shows that Mr Lim had admitted during multiple interviews with the ISD that he had met Fong three times, including once five days before the big split within the PAP in 1961. Mr Lim also said he joined the PAP at the urging of the CPM, through instructions passed down by his superior in the ABL.
Was Coldstore politically motivated?
SEVERAL former detainees like Dr Poh have alleged that Operation Coldstore had no security basis and was a political exercise meant to suppress legitimate, peaceful opponents who posed a challenge to the PAP.
Quite apart from whether the communist threat posed a real danger, or whether Barisan Sosialis leaders were communist or pro-communist, a number of the revisionist writers say declassified material from the British archives showed colonial officials at the time themselves disagreeing over whether there was enough evidence to justify the mass arrests.
Here, they focus on assessments made by British officers then based in Singapore, such as security liaison officer Maurice Williams, who concluded in April 1962 that a paper written by the Singapore Special Branch on the communist network in Singapore was entirely "surmise".
They also quote Lord Selkirk extensively as saying in October 1962 that there was not enough evidence to conclude that some of the Barisan politicians were communist, and that arresting them would be politically indefensible in both the House of Commons, and at the United Nations.
Dr Poh and historians like Dr Thum and Dr Hong home in on British officials' opinions that Mr Lee seemed taken by the idea of destroying his political opponents like Lim Chin Siong, whom he had "greatly feared (due to his) popularity with the masses".
The opinions of these officials mattered, as the sweep had to be authorised by the Internal Security Council comprising representatives from the British, Singaporean and Malayan governments.
However, officials and other historians say the revisionist accounts are based on a selective reading of documents.
Dr Kumar says the British officials' reticence in acting against alleged communists had more to do with their inexperience on the job, as they were then new to Malaya, coupled with a concern not to repeat some of the scandals that had arisen in other British colonies.
Lord Selkirk was appointed Commissioner to Singapore in December 1959, while security liaison officer Williams arrived here in March 1962, one month before he dismissed the Special Branch paper. Officials were also reluctant to act in the absence of clear evidence of an imminent security threat, Dr Kumar adds.
Across the Causeway, however, the British High Commissioner in Kuala Lumpur was warning his counterpart of the dangers of playing by the rules with the communists, while the Federation's top police officer felt British officials in Singapore were being timid.
In any case, both Lord Selkirk and his deputy were convinced of the communist threat by December 1962 - following ongoing Special Branch surveillance of Barisan committee meetings - and fired off an urgent "Top Secret and Personal" note to the Colonial Office of "conclusive evidence than we have had hitherto for the belief that Barisan Sosialis are communist-controlled".
Whether the Barisan would ever depart from trying to take over the government by constitutional and legal means if circumstances changed was also never in doubt, says Dr Kumar.
A Special Branch report had showed that the question of armed struggle had been discussed at length at a party meeting attended by about 40 Barisan CEC and Branch members.
"In April 1964, Lim himself conceded that within the Barisan there was a faction that felt that its political objectives could not be met via constitutional means and thus more drastic measures such as armed struggle should be considered," writes Dr Kumar, citing the Special Branch's report of its interview with Mr Lim.
Hence, the view that the Barisan was a legitimate political option to the PAP that was committed to principled peaceful and lawful constitutional struggle is off the mark, he argues.
He adds: "It was to all intents and purposes the 'business end' of the CUF in its final phase of effective existence, from July 1961 to February 1963."
Should more information be made public?
THE ongoing debate over revisionist accounts of Coldstore has given rise to calls for more official documents from the period to be opened up for historians to get a fuller picture of the crackdown, although some say this will take time.
These calls have been made by those behind alternative accounts of the period, and the issue was also raised by several members of the audience at Dr Kumar's book launch earlier this month, even as classified material has been made available by the Government on a case-by-case basis.
They include Associate Professor Huang Jianli of NUS' history department, who said most readers and fellow academics who wanted to access some of the primary documents, including those cited in Dr Kumar's book, are currently unable to do so.
Nominated MP and historian Tan Tai Yong tells Insight that the Government should widen access to the archives, and such access should not hinge on who is asking for them.
"If a government agency wishes to open its records, it should not do so selectively. Giving 'privileged access' creates a number of problems: Who do you give access to and why? Is it right to deny access to researchers who may take considered but contrary views to an official perspective?" he tells Insight.
"As a matter of principle, public records that are declassified should be open to all. It is not for the archives to decide if their records should be used for certain purposes only, or merely to support a particular interpretation or argument."
He also cautions against using the term "revisionist" for certain authors to imply an underlying agenda: "Not every historian who challenges existing interpretations or viewpoints is engaged in propaganda or polemics. There are those who are simply trying to write better history by offering different perspectives."
Prof Tan adds: "For a historian to do his work properly, access to records and evidence is necessary and they will then have to evaluate and weigh these evidence and facts to make sense of developments and events in their proper contexts. Without records, historians are hamstrung."
But Dr Bilveer Singh says such calls for greater access to historical documents are not falling on deaf ears, and points to a gradual opening up of the archives by the Government.
"I believe everyone, including the Government, would like to see these things opened up, but at the same time discretion and prudence should be used," he says. "We are a very young society and many issues remain sensitive, especially those with implications for race and religion, and involving our immediate neighbours."
He adds: "No one opens up everything, not even the Western democracies."
And even with greater access to documents, he feels some individuals will continue to politicise the past and undertake "the politics of cherrypicking" evidence.
Several historians have also called for something akin to the "30-year rule" adopted in places like Britain and Australia, where records are transferred to the national archives after 30 years, unless specific exemptions are given for documents deemed likely to damage the country's image, national security or foreign relations.
Dr Singh feels Singapore may eventually adopt this position but, for now, there remain "too many unsettled issues and too many people around willing to do damage".
He cites how the narrative on Coldstore from revisionists and former detainees is that "it is all done by Lee Kuan Yew and his party". "This is a total misrepresentation: it was done by the Internal Security Council with immense pressure from London and Kuala Lumpur to rein in the communists and their open-front supporters," he adds.
He also says it would be a mistake to view the policies and actions of the past through the lens of the present, citing the wider context of the Cold War and the threat posed by the Indonesian Communist Party next door.
And contrary to assertions that the Government may be wary of exposing past misdeeds, he does not think there is a need for the Government to fear "skeletons in the cupboard" should more evidence be made available.
Prominent historian Wang Gungwu says historians have sought to be rigorous in applying higher standards of objectivity, but this is a challenge where contemporary history is concerned, as there are always known gaps in the evidence and subjective interpretations are almost inevitable.
"The official (victor's) version seeks to provide the 'master narrative', usually with the advantage of having more sources at the government's disposal," he adds. Sympathisers would want to challenge such versions, even if they did not have access to the full information.
"If historians are drawn into debates on the basis of inadequate data, there is usually more heat than light," he says.
Professor Wang believes that when more evidence is made available, Singaporeans can tell the difference between an argument that is logical and evidence-based, and one that is not.
The debate over the legitimacy of Coldstore is likely to continue as further material surfaces, and as more researchers revisit the nation's recent past.
As this takes place, the hope is that more light, and less heat, will be generated.