The Nawabs under British rule and their decline edit

 
Mir Jafar meeting Robert Clive, after the Battle of Plassey
 
Flag of Bengal Presidency, under British rule

The forces of the British East India Company led by Robert Clive defeated Nawab Siraj ud-Daulah in the Battle of Plassey, in 1757. He was succeeded by Mir Jafar, who had supported Clive. Jafar briefly tried to re-assert Nawabi dominance by allying with the Dutch, but it failed following the Battle of Chinsurah. Thereafter, the Nawab had to depend on the British for military support. Jafar was defeated at the Battle of Buxar and the company was granted the diwani of Bengal by Mughal emperor Shah Alam II, in August 1765. Subsequently, Warren Hastings was appointed the first Governor General of Bengal, in 1773. By this time, the Nawab's authority stood severely restricted and the Company asserted its authority by forming the Bengal Presidency.

The company also abolished the system of dual governance.

In 1793, during Nawab Mubarak ud-Daulah's reign, the nizamat was also overtaken by the company. By taking complete control of the region, the Nawabs stood as mere pensioners of the company. The diwan offices except the diwan ton also stood abolished. Following the Revolt of 1857, Company rule in India ended, and all territories under control of the company came under the British crown in 1858, marking the beginning of the British Raj. Nawab Mansur Ali Khan was the last titular Nawab of Bengal. During his reign the nizamat at Murshidabad came to be debt-ridden. In February 1869, the Nawab had also migrated from Murshidabad and had started living in England. His was subsequently abolished in 1880. He returned to Bombay, in October 1880, and pleaded his case, but as it stood unresolved he abdicated in favour of his eldest son, Hassan Ali Mirza, at St. Ives, Maidenhead, on 1 November 1880.

 
Map dated 1907, illustrating the growth of British Bengal and British Burma
 
Map dated 1907, illustrating divided Bengal, following partition in 1905
 
Map dated 1915, illustrating the reunification of Bengal, restoration of Assam, and creation of the Bihar and Orissa province
 
Map of Bengal, dated 1880