Thum Ping Tjin

In May 2020, Thum was issued a POFMA correction order for his statements on POFMA itself. While complying with the order, Thum has said that he will appeal against the POFMA order in the court of Singapore.

In March 2018, Al Jazeera interviewed Thum for the documentary "The House That Lee Built"; Thum claimed that when he was a research fellow at NUS, he published and gave lectures about his research, which showed that Singapore's founding Prime Minister Lee Kuan Yew "had lied about his use of detention without trial from the 1960s onward." Thum further claimed that shortly afterwards, a senior staff member at NUS privately informed him that he "would never be able to work in Singapore as an academic... again".

In March 2018, in response to a call from the Select Committee on Deliberate Online Falsehoods for submissions, Thum submitted a paper arguing that any legislation by the Singapore Parliament against online falsehood must also apply to the Singapore government. He cited the government's use of detention without trial between 1963 and 1988 during Operation Coldstore and Operation Spectrum. While the government argued that the detainees were part of a communist plot or Marxist conspiracy to subvert the state, Thum claimed that the government has never produced any evidence to substantiate its claims nor have any detainees been brought to trial on the charges they were detained under. Thum argued that these justifications were false claims made by politicians of the ruling People's Action Party (PAP) for the purpose of political gain.

On 11 April 2018, the Accounting and Corporate Regulatory Authority (ACRA) notified Thum and Kirsten Han, an activist and freelance journalist, that their 18 February 2018 application to register a private company "OSEA Private Limited" was rejected. ACRA released a press statement which stated that the company was "clearly political in nature" and contrary to Singapore's national interests. According to The Straits Times, "this is the first publicised case of a proposed incorporated entity having its application rejected due to foreign funding for domestic political activities."

On 1 May 2018, Select Committee chairman Charles Chong noted that Thum and Philip Kreager – both trustees of Oxford's Project Southeast Asia – were directors of OSEA-UK on the British government's company registry.

On 30 August 2018, Thum, Tan Wah Piow and others met Mahathir Mohamad, the Prime Minister of Malaysia, and asked him to take a lead role in promoting democracy in Southeast Asia. This prompted Seah Kian Peng, a Singaporean Member of Parliament, to post on Facebook that "it appears quite clear to me that Thum does not wish Singapore well"; some people also called Thum a "traitor" online. Law and Home Affairs Minister K. Shanmugam commented that to invite "a foreign politician, to intervene in our domestic politics ... is an absolute no no". Thum rejects the notion that he is a traitor.

Since 2017, Thum has been the Managing Director of New Naratif.

On 29 March, the last day of the sitting of the Select Committee, Law and Home Affairs Minister K. Shanmugam questioned Thum about a paper he published in 2013 regarding Operation Coldstore and the formation of Malaysia. He said Thum fell short of the standards of an objective historian, saying that he "ignores evidence which you don't like, you ignore and suppress what is inconvenient and in your writings you present quite an untrue picture". Thum countered that his paper had been peer-reviewed and that no historian had stepped forward to contradict the central thrust of his work.

Thum, Kirsten Han and Jolovan Wham, who also met Mahathir, sent letters of complaint to Lee Hsien Loong, the Prime Minister of Singapore, denouncing the conduct of Seah, who is also a member of the Select Committee on Deliberate Online Falsehoods, for making serious accusations without substantiation. Han responded that Seah's Facebook post "dog-whistled to online trolls and unleashed abusive online harassment – although he's since called for civility, he has not retracted his claims nor provided evidence, and his allegations continue to provide fodder for personal attacks". The trio also urged Charles Chong, the chairperson of the Select Committee, to "take leadership in promoting responsible behaviour and engaging in evidence-based discussion".

From 2012 to 2014, Thum was a research fellow at the Asia Research Institute, National University of Singapore (NUS). Since 2014, Thum has been a research associate at Oxford's Centre for Global History; a fellow of Green Templeton College; and the coordinator of Project Southeast Asia. In 2015, Thum was elected as a Young Global Leader by the World Economic Forum.

On 6 August 2005, Thum swam solo across the English Channel in 12 hours and 24 minutes, and became the first Singaporean to do so. While preparing for his Channel swim, Thum also set a world record when he swam around the Rock of Gibraltar in 2 hours and 52 minutes.

During his studies at the University of Oxford, Thum captained the university's swimming team and earned two Blues times. In 2002, he retired from the Singaporean national swimming team but continued to represent Oxford in swimming.

At the age of 16, Thum represented Singapore in four swim races at the 1996 Summer Olympics in Atlanta:

Thum Ping Tjin (Chinese: 覃炳鑫 ; pinyin: Tán Bǐng Xīn ) (born 17 December 1979), also known as PJ Thum, is a former national swimmer, a former research fellow at the University of Oxford and read history at his alma mater. He was the coordinator of Project Southeast Asia, a collective of scholars of Southeast Asia at the University of Oxford. The first Singaporean to swim the English Channel, he represented his country in four swim races at the 1996 Summer Olympics.

Born on 17 December 1979 in Singapore, Thum received his early education at five of the Anglo-Chinese Schools.