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The 1967 by-elections were held on 7 March 1967, precipitated following a series of resignations of Barisan Sosialis's MPs which occurred the year before on 5 December 1966.
A total of 12 MPs resigned a year prior, 11 of which from Barisan Sosialis, who resigned their seats citing that Lim Huan Boon, who initiated the mass exodus, claimed Singapore's independence was "phony" because no discussion of Singapore's separation matter was made in the legislature. Six of the vacated seats had by-elections prior, while the other five, Koo Young, Loh Miaw Gong, Ong Lian Teng, Poh Ber Liak and Tan Cheng Tong, resigned on 5 December. The seats for Bukit Panjang, Havelock, Jalan Kayu, Tampines and Thomson, respectively, were therefore vacant, and polls adjourned on 7 March. On nomination day on 24 February, only Thomson had a contest involving a multi-cornered fight with two independents.
Much like the previous year's by-election, oppositions would see downturn and the Barisan Sosialis lost credibility. By the end of the following year's election, the last two Barisan MPs Chan Sun Wing (Nee Soon) and Wong Soon Fong (Toa Payoh) had opted to flee the country in order to avoid being arrested by the Internal Security Department (ISD) as what happened to their colleague Chia Thye Poh and others, completing PAP's government monopoly.
The results in the by-election where both independent candidates had their election deposits forfeited proved that PAP would be dominant onto government control and trustworthiness of voting electorate. Opposition would not win any of the election again for the next 14 years until 1981.