Prime Minister of Thailand Rajanubhab took over this role. In fact, the office most considered the precursor of that of the prime minister was the ancient office of "Samuha Nayok" (สมุหนายก), which was run by an "Akkhra Maha Senabodi" (อัครมหาเสนาบดี) or "chief minister in charge of civilian affairs". The first Prime Minister of Siam was Phraya Manopakorn Nititada, a judge. The title of the office was changed from "Prime Minister "of Siam"" to "Prime Minister "of Thailand"" in 1945 and then permanently with the renaming of Siam to Thailand in 1949. For most of its existence the office has been occupied by Army leaders;
2014 interim constitution of Thailand which the NCPO leader can issue any order at will for the sake of the reforms or security. All orders so issued are considered lawful and final. Public discussions about the interim constitution are prohibited by the NCPO. After months of political crisis in which former Democrat Party secretary general Suthep Thaugsuban led a street protest against the government of Prime Minister Yingluck Shinawatra, the Royal Thai Armed Forces staged a coup d'état unseating the government on 22 May 2014. On that day, the military formed the NCPO to rule the nation and partially repealed the 2007 constitution, keeping intact