What were the reasons which made Bengal an easy prey to the imperialistic ambitions of the British?

The reign of Murshid Quli Khan, Shuja-ud-din and Alivardi Khan gave Bengal a long period of peace and promoted trade and commerce. As a result of this, Bengal prospered. However, these Nawabs did not check the agressive and expansionist policies of the English East India Company. In fact they could not understand the true nature and ulterior motives of the East India Company. Corruption was rampant and even the high ranking officals were involved in it. They did not build a strong army and paid a heavy price for it. Due to these reasons, Bengal became an easy prey to the imperialistic ambitions of the British.