Following are the responsible reasons for the Battle of Plassey:

1. Siraj-ud-Daula who was impulsive by nature was ruling over Bengal.
2. He had some opponents in his state.
3. During this period under the pretext of security reasons, British built a fortress around the trade centre in Calcutta (Kolkata) without taking the permission of the Nawab.
4. Nawab destroyed it.
5. When this news reached Madras, a small army under the Company reached Bengal under the leadership of Robert Clive.
6. But Clive realized that it was not easy to defeat the Nawab’s army.
7. He planned a conspiracy to defeat the Nawab. Mir Jafar, the Commander-in-Chief of Nawab and Seth Amir chand joined him.
8. Finally a war was declared at a ground near a village named Plassey.
9. In this war, Siraj-ud-Daula was defeated. Due to Clive’s treachery the Battle ended in just half of a day.
10. Company got freehold over 24 Parganas and Mir Jafar became the Nawab of Bengal.
11. Thus, the foundation of British rule in India was laid with the Battle of Plassey in 1757.