The results of the 1957 elections came as a severe shock to Burnham and his followers. Sydney King, who was unsuccessful as an independent candidate, shortly after, joined Burnham=s party which renamed itself the People's National Congress (PNC).

At a special congress held on the 5-6 October 1957 at the Astor Cinema in Georgetown, the following officers were elected: Forbes Burnham, leader; Dr. Lachmansingh, chairman; Francis Da Silva, first vice-chairman; Jai Narine Singh, general secretary; Andrew Jackson and Jessie Burnham, assistant secretaries; Stanley Hugh, treasurer. The executive council also included Dr. J.A. Nicholson, George Young, Mrs. Mentore, Curtis Charles, Brentol Blackman, M. Edinboro, Sydney King and Jane Phillips-Gay. (Jessie Burnham resigned from the PNC in 1958 and two years later rejoined the PPP).

The election of King, who was regarded as a "black nationalist" did not seem to win the support of Jai Narine Singh, one of the few Indians in the party's leadership structure. Early in 1958, Singh resigned from the PNC and organized his own party which he called the Guiana Independence Movement. Sydney King was then named general secretary. By his inclusion in the top leadership, the PNC was able to win the support of the great majority of Africans on the East Coast Demerara, and this certainly helped to polarize party politics along racial lines.

The PPP, in the meantime, continued to command the support of a significant proportion of the African population. This proved to be worrisome for Burnham who decided to form an alliance with the African middle class from whom he had previously received little support. His plan was to organize the influential anti-PPP African politicians under his banner with the hope that they would attract all the Africans in the country to the PNC.

The African middle class was represented by the United Democratic Party (UDP), led by John Carter. Late in 1958, Burnham started negotiations with the UDP, and finally, in March 1959 the two parties held a joint congress in Georgetown. The UDP disbanded itself and merged with the PNC and the joint membership elected a new executive committee. Burnham was elected leader, and the executive committee included his close supporters, Sydney King and Andrew Jackson. Prominent members of the disbanded UDP such as John Carter, Eugene Correia and Neville Bissember were also elected.

The leaders of the PNC believed in different ideologies. Some were socialists while others, particularly the former UDP members, were strongly conservative and pro-capitalist. Their conflicting views were often expressed at public meetings and obviously generated confusion among their rank and file supporters. The party, therefore, had great difficulty in formulating an official policy statement. An agreement on a policy statement was not arrived at until early 1961 when Burnham invited Rawle Farley, a Guyanese economist at the University of the West Indies, to mediate with the members of the executive committee.