Soulbury Constitution

During the Second World War, a commission led by Lord Soulbury was sent to Ceylon to commence discussions on self-government, in recognition of the loyal service made by Ceylon and the Board of Ministers to the British war effort. D. S. Senanayake presided over the negotiations for independence. Though initially only a larger measure of self-government was being considered by the commission, the logic of history and the imminent independence of India prompted Britain to agree to the request for independence.

The new Constitution, under which Ceylon became independent in February 1948, abolished the State Council, which had encouraged a sense of responsibility regarding government in all members of the legislature. It introduced instead an oppositional system that was based almost entirely on the British cabinet system. After the parliament was elected, the person who commanded the confidence of a majority of the members of parliament was appointed prime minister, and he then appointed a cabinet to exercise executive power.

In the first parliament that was elected there was no clear majority for any single party. However, D. S. Senanayake managed to put together a coalition, consisting of his own United National Party (with which S. W. R. D. Bandaranaike had already merged his Sinhala Maha Sabha), Goonesinha's Labour Party, G. G. Ponnambalam's Tamil Congress, and some other independent politicians. The British system (or the Westminster system, as it is termed, after the site of the British Parliament), institutionalises oppositional politics. Accordingly, Sri Lanka now had a leader of the opposition, N. M. Perera, who was the leader of the Lanka Sama Samaja Pakshaya, a Trotskyist grouping.