In December 1756, Siraj-ud-Daulah’s main force left Calcutta as British didn’t t had enough military strength to challenge the Nawab of Bengal in the battlefield. The British sent Colonel Robert Clive and
Royal Navy Admiral Charles Watson from Madras to Bengal to topple the Nawab by
a palace coup. The small 2000 force landed in Bengal on January 1757.
On 9th January 1757, Clive captured the town of Calcutta.
on 3rd February 1757 with strong
18,000 cavalry, 25,000 infantry, and 40 guns Siraj-Ud-Daulah seized and camped outside
Maratha Ditch -. In military strength, Clive was dwarfed by Nawab Army, As a last resort
Clive decided to launch a surprise attack on the Nawab’s camp on the morning of 4 February under heavy fog to kill the Nawab.
Clive had intended to use a narrow raised causeway, to attack the Nawab’s quarters.
The Nawab’s troops had barricaded the passage. As the fog began to lift, the troops were overwhelmed by the discharge of heavy cannon from across the Maratha Ditch by the Nawab’s artillery.
The Nawab troops then made bridges, crossed the Maratha Ditch and reached the fort, William.
The British troops were assailed on all sides by cavalry and musket-fire of . Robert Clive surrendered to
Nawab Siraj Daula .
Siraj-ud-Daulah’s spare the life of all captured British forces, British asked to sign a treaty, He changed the name Calcutta to Alinagar and signed the Treaty of Alinagar & restored former privileges of British to do business.
On 14 June, Clive sent a declaration of war to Nawab Siraj ud-Daulah. On 15 June,
Siraj ud-Daula attacked on Mir Jafar’s palace in suspicion of his alliance with the British, Siraj obtained a promise from Mir Jafar to not join the British in the field of battle. Siraj trusted Mir Jaffer, he left the command of 16000 of his troops under Mir Jaffer.
A British Royal Navy squadron was present in the Bay of Bengal, commanded by Vice Admiral Watson.
On 17 June
Jafar had sent messages to Clive, declaring his intention to uphold the treaty between them .
he could not deploy his entire force against the British for fear of being attacked from the flanks .
fear of attack from the north by the Afghans under Ahmad Shah Durrani and from the west by the Marathas