In the national elections held on 30 May 1959, the PAP won 43 of the 51 seats in the legislative assembly. Singapore gained self-government with autonomy in all state matters except defence and foreign affairs, and Lee became the first Prime Minister of Singapore on 3 June 1959, taking over from Chief Minister Lim Yew Hock.[29]
A key event was the motion of confidence in the government, in which 13 PAP assemblymen crossed party lines and abstained from voting on 21 July 1961. Together with six prominent left-leaning leaders from trade unions, the breakaway members established a new party, the Barisan Sosialis.