National Party (PNP). [ edit ] Opposition of the SLPP government On 24 September 1960, Outspoken critic of the SLPP government, Siaka Stevens, formed an alliance with several prominent northern politicians including Sorie Ibrahim Koroma , Christian Alusine-Kamara Taylor , Mohammed Bash-Taqui , S.A.T. Koroma , Kawusu Konteh , Allieu Badarr