The peace terms of the Nawab actually failed to please the English. The bitter memory of the ‘Black-Hole Tragedy’ was still reminding Clive of the cruel atrocities of the Nawab. He wanted to take revenge upon Siraj by ousting his from the throne of Bengal.
Clive made the best use of the political situation in the court of the Nawab, which was nothing but treachery, deceit and treason. By 1756, the Seven Year’s war had already started in Europe. As a result the English captured the French settlement at Chandernagr in 1757. Clive apprehended a possible attack from the side of the Nawab who had provided shelter one some French fugitives from Chandernagar.
With a view to counteracting any such possible design of the Nawab against the English in Bengal, Clive fostered and joined a conspiracy which was already in the offing in the Nawab’s court. He observed that the notable nobles of the Nawab were not loyal to their master. They were rather dissatisfied with the Nawab Siraj-ud-daula and planning sincerely to place his Commander-in-Chief Mir Jafar on the throne of Bengal. Mir Jafar was the brother-in-law of Alivardi Khan.
The Chief persons who took part in this conspiracy were Rai Durlabh, treasurer of the Nawab, and Jagatseth, the richest banker of Bengal. Clive joined the conspiracy through a rich Bengali merchant named Amir Chand or Omichand.
It was agreed that Clive would march to Plassey and Mir Jafar would join him with all forces at his command. In return Mir Jafar would be made the Nawab of Bengal and then he would confirm all the privileges to the company. Besides, Mir Jafar promised to pay 175 lakhs of rupees to the company.
All these terms between Mir Jafar and Clive were made solely through Omichand who demanded 30 lakhs of rupees as a reward for his service. He went other the extent of intimidating Clive on this issue.
He told Clive frankly that he would divulge the whole matter to Siraj-ud-daula if he was not paid the above amount. But Clive knew how to save the situation. He got prepared two drafts of the agreement of which one was counterfeit and other a genuine one.
In the genuine agreement there was no mention of the amount to be paid to Omichand. It was signed by Clive, the members of Secret Committee and Admiral Watson.
The second draft which was a counterfeit one contained the agreement regarding the payment of the above amount to Omichand. It was signed by Clive and the members of the secret Committee. But Watson being a conscientious person refused to sign the false draft. Clive forged the signature of Watson on the counterfeit agreement and showed it to Omichand. It was a clear proof of Clive’ this meanness.
When the ground was thus prepared and the plot was ripe, Clive picked up a quarrel with Siraj-ud-daula by writing him a letter of allegation. He alleged that Siraj had broken the terms of the Treaty of Alinagar by providing shelter to the French. With this much of accusation Clive marched his army towards Murshidabad and reached Plassey on the 23rd June 1757 with about 32,00 soldiers.
The Nawab had as many as 50,000 soldiers. But as they were commanded by Mir Jafar, who played treachery with Siraj, they were not properly brought into action. Consequently flee from the battle ground for his dear life. But he could not escape safely. He was caught on the way by Miran, the son of Mir Jafar, who put him to death immediately. Thereafter, according to the previous agreement, Clive placed Mir Jafar on the throne of Bengal. Mir Jafar paid Clive a sum of rupees 234, 000 for his personal fund. He also pleased the company by paying it a sum of rupees fifty lakh and ceding to it the twenty- four Parganas.