The Anson by-election, 1981, was held in Singapore on 31 October 1981 to choose a representative for the constituency of Anson in Parliament. It was triggered by incumbent MP Devan Nair stepping down in order to become President of Singapore (succeeding Benjamin Sheares, who had died on 12 May 1981). The by-election was won by the leader of the Workers' Party, J.B. Jeyaretnam, defeating the candidate of the governing People's Action Party (PAP), Pang Kim Hin. The by-election marked the first occasion since Singapore's independence in which a PAP candidate was defeated in an election for a seat in Parliament.
The Nomination Day for the by-election was 21 October 1981. The election deposit for candidates was set at $1500. Three candidates stood in the by-election: Pang Kim Hin of the PAP, J.B. Jeyaretnam of the Worker's Party and Harbans Singh of the United People's Front (UPF). The leader of the Singapore Democratic Party (SDP), Chiam See Tong, also considered standing in the by-election, but decided to withdraw at the last minute and leave Jeyaretnam to be the PAP's main opponent in the name of "opposition unity".
Note: As Habans Singh of United People's Front failed to garner the minimum 12.5% (one-eighth) of the votes necessary to keep his deposit, his election deposit was forfeited.
A number of factors are thought to have contributed to ruling party's defeat in this by-election. One of them was the fact that he Pang a new face to the public in Singapore whereas Jeyaretnam was a veteran of several general elections and by-elections (though this was the first time he had stood in Anson). Another factor may have been that Pang did not make use of Anson's grassroots leaders during his campaign, upsetting some of them, and that he did not connect effectively with working-class people in the constituency. Another issue surrounding the campaign was that residents in the Blair Plain area of the constituency were unhappy that they were not being given priority for HDB flats when their homes were being demolished to make way for a new Port of Singapore Authority container complex, and some voters may have used the by-election as an opportunity to express discontent regarding this.