Question

how was bengal brought under british control

Answer 1

Murshidabad remained the capital of the Nawabs of Bengal until their rule. The Nawab Siraj ud-Daulah, was betrayed in the Battle of Plassey by Mir Jaffer. ... In 1772 the Dual Government system was abolished and
Bengal was brought under direct control of the British .

Answer 2

duvide and rule was implemented which made it separate in 2 parts west and east bengal fights began and the britishers took advantage of it