Barisan Sosialis's elected Members of Parliament have heeded to Lim Huan Boon's call on the grounds that Singapore's independence was "phony" because no discussion of Singapore's separation matter was made in the legislature. The final walkout of Barisan members were Koo Young, Loh Miaw Gong, Ong Lian Teng, Poh Ber Liak and Tan Cheng Tong, and left five constituencies vacant; Bukit Panjang, Havelock, Jalan Kayu, Tampines and Thomson respectively. As a result, by-elections were held on 7 March 1967, with the nomination day held on 24 February 1967. Despite five constituencies were vacant, only Thomson was contested by two independent candidates a PAP candidate—in which PAP won. PAP also won the other four constituencies by an uncontested walkover.
The election deposit was set at $500. Similar to previous elections, the election deposit will be forfeited if the particular candidate had failed to secure at least 12.5% or one-eighth of the votes.
After this by election which saw both independent candidates obtaining less than one-eighth of the votes and had their election deposit forfeited, the parliament is effectively held only by the PAP Members until the famous 1981 Anson by election as the other 2 BS members Chan Sun Wing (Nee Soon) and Wong Soon Fong (Toa Payoh) had opted to flee the country in order to avoid being arrested[1] by the Internal Security Department (ISD) as what happened to their colleague Chia Thye Poh and others.