Between 1963 and 1965, Singapore was a part of Malaysia and the PAP functioned as a Malaysian party. However, the prospect that the PAP might rule Malaysia, upset PAP relations with UMNO and the Malay nationalist belief in the Tanah Melayu. The clash of personalities between Lee Kuan Yew and the Malaysian Prime Minister resulting in an ensuing crisis, and led to Singapore's separation from Malaysia.
Originally a socialist party, the PAP Executive later expelled the leftist faction, bringing the ideological basis of the party into the centre, and later in the 60s, moving further to the right.
For many years the party was led by Lee Kuan Yew, who was prime minister from 1959 to 1990. The current prime minister, and secretary general of the PAP, is Goh Chok Tong, and the current deputy prime minister, is Lee Hsien Loong, Lee Kuan Yew's son. Lee Hsien Loong will become the next prime minister after Goh Chok Tong steps down.
Even though the PAP can be credited with the economic success of Singapore,it has ruled the country with an iron-fist where it controls the media, suppresses political dissent and often silences its opponents with law suits.