The " independent , sovereign republic of Bangladesh " was first proclaimed in a radio message broadcast from a captured station in Chittagong on 26th March in1971 . Two days later , The " Voice of Independent Bangladesh " announced that a " Major Ziaur Rahman " [actually Ziaur Rahman, later president of Bangladesh] would form a new government with himself occupying the "presidency". Zia self appointment was considered brash , especially by Mujibur Rahman , who in subsequent years would hold a grudge . Quickly realizing that his action was unpopular , Ziaur Rahaman yielded his " office " to the incarcerated Mujibur Rahaman .
The following month a provisional government was established in Calcutta by a number of leading Awami League members who had escaped from East Pakistan . On 17th April in 1971 , the " Mujibnagar " government formally proclaimed independence and named Mujibur Rahaman as its president . On 6th December in 1971 , India became the first nation to recognize the new Bangladeshi government . When the West Pakistani surrender came ten days later , the provisional government had some organization in place , but it was not until December 22 that members of the new government arrived in Dhaka , having been forced to heed the advice of the Indian military that order must quickly be restored . Representatives of the Bangladeshi government and the Mukti Bahini were absent from the ceremony of surrender of the Pakistan Army to the Indian Army On 16th December in 1971 . Bangladeshis considered this ceremony insulting , and it did much to sour relations between Bangladesh and India .
At independence , Mujibur Rahaman was in jail in West Pakistan , where he had been taken after his arrest On 25th March in 1971. He had been convicted of treason by a military court and sentenced to death . Yahya did not carry out the sentence , perhaps as a result of pleas made by many foreign governments . With the surrender of Pakistani forces in Dhaka and the Indian proclamation of a cease-fire on the western front , Yahya Khan relinquished power to a civilian government under Bhutto , who released Mujib and permitted him to return to Dhaka via London and New Delhi .
On January 10, 1972, Mujibur Rahaman arrived in Dhaka to a tumultuous welcome. Mujib first assumed the title of president but vacated that office two days later to become the prime minister. Mujib pushed through a new constitution that was modeled on the Indian Constitution. The Constitution--adopted on November 4, 1972--stated that the new nation was to have a prime minister appointed by the president and approved by a single-house parliament. The Constitution enumerates a number of principles on which Bangladesh is to be governed. These have come to be known as the tenets of "Mujibism" (or "Mujibbad"), which include the four pillars of nationalism, socialism, secularism, and democracy. In the following years, however, Mujib discarded everything Bangladesh theoretically represented: constitutionalism, freedom of speech, rule of law, the right to dissent, and equal opportunity of employment .