Ong later resigned his seat in Hong Lim on 29 December and later expelled by the party after making open disputes with his Cabinet colleagues, including over the abolishment of the City Council when he was the last Mayor.

On 20 April, nine days prior to the first by-election polling, another seat was vacated following the death of Anson's MP Baharuddin Mohammed Ariff.

Incidentally, the PAP candidate Jek Yeun Thong was Ong's secretary during his time as Mayor in the City Council.

Marshall's victory marked the first WP presence in the legislature and the return to the Assembly since his resignation from the Labour Front in 1956; however, he lost his re-election bid in 1963.

Two days after the Anson by-election, Prime Minister Lee Kuan Yew tendered his resignation and handed his role to the party's chairman Toh Chin Chye, who declined.