Potong Pasir Single Member Constituency

1984–1996: SDP era

During the 1984 general election, Chiam contested Potong Pasir for the SDP again. Howe retired from politics that year and did not stand for reelection; PAP newcomer Mah Bow Tan was sent to retain the constituency.^[12][13] Leading up to the election, then-Prime Minister Lee Kuan Yew compared Chiam and Mah's O-Level (GCE Ordinary Level) results in a rally speech, saying, "Mah Bow Tan, age 16, took his O-Levels — six distinctions, two credits. Mr Chiam, age 18 — six credits, one pass." The Prime Minister's Office later conveyed an apology from Lee for making an error about Chiam's results; Chiam had actually gotten seven credits.^[14] Chiam was elected MP for Potong Pasir after winning the election with 60.28% of the vote.^[15]

In 1988, the constituency was renamed Potong Pasir Single Member Constituency with the creation of group representation constituencies (GRCs).^[16] Chiam retained his seat with an improved 63.13% of the vote against PAP candidate Kenneth Chen Koon Lap.^[17]

In 1991, Chiam won reelection with 69.64% of the vote against PAP candidate Andy Gan.^[18][19]

1997–2011: SPP/SDA era

In December 1996, when Parliament was dissolved ahead of the 1997 general election, Chiam left the SDP and joined the Singapore People's Party (SPP), formed from a pro-Chiam former SDP faction which had left in 1994.^[19] He assumed leadership of the SPP and stood for reelection in Potong Pasir SMC under its banner, becoming the first SPP MP after winning 55.15% of the vote against Gan.^[19][20]

2011: PAP gain/entry of Sitoh Yih Pin into Parliament

In the 2011 general election, Chiam did not stand for reelection in Potong Pasir SMC, instead leading an ultimately defeated five-member team to contest the neighbouring Bishan–Toa Payoh GRC.^[27] His wife, Lina Loh,^[b] became the SPP candidate for the SMC; a recount confirmed that Sitoh defeated her by 0.72% of the vote, or 114 votes.^[23][28] She was offered, and accepted, the first of three non-constituency MP (NCMP) seats issued after the election.^[29][30] While Chiam stated his opposition to the NCMP scheme, the SPP reasoned that it was "critical" to ensure an "alternative voice in Parliament", and that having a presence in Parliament would allow the party to "remain engaged in national issues" and be publicly visible until the next election due by 2016. Loh also claimed that she had accepted the post to fulfil the "wishes" of residents of the constituency and because she considered her losing margin "too small".^[30]

2015: PAP entrenchment

In the 2015 general election, Sitoh retained his seat with 66.41% of the vote in a rematch against Loh, who did not return to Parliament.^[23][28]

2020: Change in boundaries

Prior to the 2020 general election, the first polling district of Potong Pasir SMC was transferred to the 4-member Bishan–Toa Payoh GRC;^[27] in return, the SMC absorbed the Joo Seng area of Marine Parade GRC.^[27][31] Sitoh defeated SPP candidate Jose Raymond with 60.67% of the vote, winning a third term in Potong Pasir SMC.^[32][28]

2025: Population increase/retirement of Sitoh

Interactive map of Potong Pasir SMC as of the 2025 general election

For the 2025 general election, after an increase in population due to Build-To-Order (BTO) developments in the Bidadari area under Potong Pasir SMC, the EBRC returned two of its polling districts to the new Marine Parade–Braddell Heights GRC, the successor to the now-defunct Marine Parade GRC.^[28][33][34] At that election, the SMC had 30,971 registered voters, an increase of 67% from 2020.^[28]

On 16 April, it was announced that Sitoh would retire from Parliament and that he would be replaced by Alex Yeo, a former branch chairperson^[c] for the PAP in the Paya Lebar division of WP-held Aljunied GRC.^[37] On 22 April, the SPP announced that party treasurer Williamson Lee would contest the constituency.^[39] On nomination day, Lim Tean, secretary-general of the People's Alliance for Reform (PAR), a political coalition, was also nominated to contest the constituency, resulting in a three-way fight between the PAP, SPP and PAR.^[34] Yeo proceeded to win 69.2% of the vote against Lee's 22.46% and Lim's 8.33%; Lim lost his electoral deposit of $13,500 for not obtaining at least 12.5% of the vote.^[28][40][41]