SINGAPORE - On Tuesday night (Nov 30), Ms Raeesah Khan resigned from the Workers' Party and Parliament, which removes her from her role as an MP for Sengkang GRC.

This follows her admission on Nov 1 in Parliament to lying about a purported incident where she claimed the police mishandled a rape victim's complaint. The allegation was first made in Parliament in August.

She was referred to the Committee of Privileges for a breach of parliamentary privilege following the admission.

What happens next? The Straits Times explains.

1. What happens in Sengkang GRC? Will there be a by-election?

It is unclear.

In 2017, when President Halimah Yacob, who was then an MP for Marsiling-Yew Tee GRC, resigned from her parliamentary seat to contest the presidential election, there was no by-election called.

Replying to a query from Aljunied GRC MP Pritam Singh during the Second Reading of the Presidential Elections (Amendment) Bill in Parliament on Feb 6 that year, then Minister in the Prime Minister's Office Chan Chun Sing said that there is no need to hold a by-election for a GRC if a member of the team resigns.

It is possible that the rest of the Sengkang GRC team - Ms He Ting Ru, Associate Professor Jamus Lim and Mr Louis Chua - could step down from their seats, triggering a by-election.

By-elections have been held 13 times since the independence of Singapore, with the latest being held in 2016 to fill a vacancy arising in Bukit Batok SMC.

2. What does the law say about by-elections?

The Parliamentary Elections Act states that a Writ of Election shall be issued only if all the MPs for the GRC have vacated their seats. If only one of the MPs vacates his or her seat, the needs of residents in the GRC would continue to be served by the remaining members of the GRC team.

In 2019, Singapore's apex court dismissed an appeal for the remaining three MPs in Marsiling-Yew Tee GRC to vacate their seats and for a by-election to be called in the constituency following Madam Halimah's resignation as an MP in 2017.

Referencing the relevant parliamentary debates in 1988, the Court of Appeal said it is clear that Parliament had decided there would be no obligation on the Government to call a by-election in a GRC when a single vacancy arises.

This arrangement, it was decided then, was preferable to the alternative - of the possibility that one member of a GRC team could hold the other members of the team to ransom.

In the case where the vacancy was previously filled by a minority member and minority representation in Parliament would be diminished if the seat was left unfilled, the court said that Parliament had decided this risk was an acceptable trade-off for preventing the situation of an MP holding other members of the team ransom.

3. Will Ms Khan's matter still be heard by Parliament's Committee of Privileges?

In a statement on Wednesday, the Office of the Clerk of Parliament said that the Committee of Privileges will continue with its work on the matters pertaining to the complaint referred to it on Nov 1.

Leader of the House Indranee Rajah had raised a formal complaint against Ms Khan for breaching her parliamentary privilege on Nov 1.

The Office of the Clerk of Parliament also said that the Parliament (Privileges, Immunities and Powers) Act regulates the conduct of MPs and other persons in connection with its proceedings, and the committee can summon any person to appear before it to give evidence at any time before the conclusion of its report.

The committee will present its report to Parliament in due course, it added.

In her resignation letter, Ms Khan said that she will assist the committee with its work.

4. What impact will this have on the Workers' Party?

How it might play out remains to be seen, but discussions are sprouting across social media.

Political observer Derek da Cunha said in a Facebook post on Wednesday morning that the decision for Ms Khan to resign was "not unexpected" and "on many levels, it is also an entirely right decision".

He said that the decision was a good one for both Ms Khan and the WP.

"The areas she had focused on and, inadvertently, typecast her as heavily ideological - a social justice warrior (SJW) - have tended to spawn unnecessary side issues for the WP, distracting the party from its key efforts in assisting the greatest number of Singaporeans in their economic challenges," he said.

Former Nominated MP Calvin Cheng also posed questions to the WP.

He asked: "What did they know about the lies? When did they know this? And what did they do with this knowledge?"

Assistant Professor Walid Jumblatt Abdullah from Nanyang Technological University's School of Social Sciences said that Ms Khan's decision to step down after realising that she had made a mistake was right.

But he added: "I think she was a trailblazer in many ways. The first opposition minority woman parliamentarian; the first 'woke' politician in Parliament; and in GE2020, she inspired many youngsters."

5. When was the last time an MP vacated his or her seat and what happened? How many such cases have we had?

The last time an MP vacated a seat was when Madam Halimah resigned as an MP to contest the 2017 presidential election.

As she was a member of Marsiling-Yew Tee GRC, a by-election was not called and the rest of the team covered her ward instead.

Another instance was in 2016, when then People's Action Party MP David Ong resigned, citing a personal indiscretion, from his Bukit Batok SMC seat, triggering a by-election.

Mr Murali Pillai of the PAP won against Singapore Democratic Party's Dr Chee Soon Juan with 61.2 per cent of the vote.

In 2012, then Speaker of Parliament and PAP MP Michael Palmer resigned from his Punggol East SMC seat after admitting to an extramarital affair.

The subsequent by-election in January 2013 saw a four-way fight between Mr Kenneth Jeyaretnam of the Reform Party (1.2 per cent), Mr Desmond Lim Bak Chuan of the Singapore Democratic Alliance (0.57 per cent), PAP's Dr Koh Poh Koon (43.7 per cent) and the eventual victor - Ms Lee Li Lian of WP (54.5 per cent).

Also in 2012, Hougang MP Yaw Shin Leong was expelled from the WP following allegations of extramarital affairs. The party said he had failed to uphold transparency and accountability.

The by-election then saw WP's Mr Png Eng Huat defeat PAP's Mr Desmond Choo with 62.1 per cent of the vote.

In 2008, Jurong GRC MP Ong Chit Chung died suddenly at home of a heart attack at age 59.

A debate ensued on whether there was a need to call for a by-election. The seat was left vacant until the next general election in 2011.