Workers' Party assistant secretary-general Pritam Singh, 41, looks set to take over from party chief Low Thia Khiang next year, a move that may usher in a more assertive stance by the WP.

Party insiders see him as the front runner, calling it his race to lose, The Straits Times learnt from interviews with more than a dozen current and former WP members.

But Mr Singh declined to fuel speculation.

Asked last night if he would consider stepping up to the plate, he said: "It's quite premature for me to even consider this... At the end of the day, it doesn't matter whether you want it or not. It's who the party cadres want to represent the party as secretary-general."

His emergence as the favourite comes after Mr Low said at the party's 60th anniversary dinner this month that he will not contest the post of secretary-general, which he has held for 16 years.

Mr Singh leads the pack for a few reasons, said WP members, most of whom asked not to be named, citing party rules.

First, party cadres - who will choose the secretary-general at an election due next year - will likely favour an elected MP as WP chief, over a Non-Constituency MP.

The party has nine MPs, of whom six are elected.

The second reason: Mr Low's stepping down is part of a larger move to renew the WP's leadership, and this narrative would be placed in doubt if he hands over to someone in his or her 50s with fewer years left in politics. Mr Low is 61.

"If they pick Sylvia Lim, Chen Show Mao or Png Eng Huat as the next leader, it will not be renewal," said former WP executive council member Goh Meng Seng, referring to the three elected MPs who are aged, 52, 56 and 55 respectively.

Mr Singh and Mr Faisal Manap, 42, are the only elected MPs in their 40s, and most agree Mr Faisal is not eyeing the post of leader.

Mr Chen, who ran unsuccessfully for the top post last year, is unlikely to stand again as he does not have the numbers, some members said.

That leaves Mr Singh.

He has taken on a higher profile than other MPs of late. He was made assistant secretary-general, and chairs the Aljunied-Hougang Town Council (AHTC) and the WP 60th anniversary committee.

He has also done more media interviews - a telling sign in a party that tightly controls who can do such interviews, members said.

Also, he received the most votes at last year's executive committee election, a show of his standing among cadres. Mr Low and Ms Lim were not on the ballot, as they were earlier elected secretary-general and chairman respectively.

"The question now is whether Pritam wants the top job. Given he accepted the assistant secretary-general post, which is seen as the post for the next in line to be chief, the answer is clear," said a party member.

One big uncertainty is the lawsuit brought against WP MPs by an independent panel representing AHTC. Mr Low and Ms Lim are named in claims hitting $33 million. Mr Singh is less exposed. He is tied to $2.8 million in claims, and even then, he is held collectively accountable with four others.

However, "if more damage comes from the suit prior to party elections, he could lose his front-runner status," said a member.

What would the WP look like under Mr Singh?

WP members say he will continue focusing heavily on ground work, engaging voters door-to-door and meeting local needs.

Some added that he has shown signs of being more combative than Mr Low in Parliament - with one senior member expecting a WP "somewhere between that of Mr Low and Mr J.B. Jeyaretnam".

The late Mr Jeyaretnam, who led the WP before Mr Low, was known for his hard-hitting criticism of the ruling party.

Associate Professor Eugene Tan, of the Singapore Management University and a former Nominated MP, expects more assertiveness by WP and greater weight on some issues, such as race and religion, the rule of law and social justice.

Mr Singh has his work cut out for him. Members say that should he ascend to the post, his first job would be to unite all factions.

One veteran member noted that he has started seeking reconciliation by meeting "rebel cadres" who supported Mr Chen's challenge for the top job last year.

"There will be more collective leadership in future - not one sun, but many suns," a member said.

After stabilising the ship, members say his first major test will be the next general election, due in 2021. Added a former member: "If the party does badly, his leadership may not survive it."