Ponnambalam's decision to join the UNP led government in 1948 caused a split in the ACTC. Eventually, in December 1949, the ACTC dissidents, led by Chelvanayakam, C. Vanniasingam and E. M. V. Naganathan, formed the Illankai Tamil Arasu Kachchi (ITAK, Federal Party). As Ceylon's two main parties, the UNP and Sri Lanka Freedom Party (SLFP), introduced policies, such as the Sinhala Only Act, which further discriminated against the country's minorities, ITAK's Tamil nationalism became more popular than the ACTC's conservatism. At the 1956 parliamentary election the ITAK overtook the ACTC as the most popular party amongst Ceylon Tamils.