Why is the Indian Council Act, 1861 known as the ‘prime charter of the Indian Legislature?

The Indian Council Act 1861 came to be known as the ‘prime charter of the Indian Constitution’ because it made several reforms in the legislative affairs. The act established the Legislative Councils at the centre, presidencies and provinces. The Council of the Governor General was reconstituted under this Act. An assurance was given that Indians would be appointed to the Council. The Council failed to function anywhere near to a responsible or representative legislative body. However, for the first time in the history of British rule in India, the Council recognized the importance of non-officials in legislative bodies.