There were 3 By-elections held within 1966, with the first triggered just 4 months the expulsion from Malaysia on 8 December 1965. Lim Huan Boon from Barisan Sosialis (BS), who started the trigger of the BS boycott of Parliament because they claimed that Singapore's independence was "phony" on the grounds that the separation matter was not discussed in the legislature and announced that all of its MPs would resign their seats and take their struggle for democracy onto the streets. Hence, with the exception of Dr Fong Kim Heng from People's Action Party who resigned his seat on November, 6 other vacant constituencies are caused by the mass resignation from the members of BS legislators that are divided into 3 phases that triggers 3 different by-elections in the year, namely, January, March