What are the political causes for the revolt of 1857?

The British policy of annexation led to the displacement of a large number of rulers.

The strict enforcement of the policies of subsidiary alliance and doctrine of lapse made the ruling sections of society very unhappy. Rani Lakshmi Bai and Nana Sahib became the enemies of the British and led the revolt in their respective territories.

the annexation of Awadh on grounds of misgovernment, was greatly resented. The Nawabs of Awadh had been loyal to the British. The annexation was widely seen as an act of betrayal by the British. It deeply hurt the sentimes of the Company's sepoys because most of them came from Awadh, the people there got no relief from oppression. Peasants had to pay even higher revenue and additional taxes were imposed. The British provided no alternative source of employment to the people who lost their jobs due to the collapse of the Nawab's administration.