Around 1905, Bengal had become the nerve centre of the Indian nationalism. official version of the reasons that led to the partition of Bengal was administrative convenience. It was said that the existing province of Bengal was too big to be efficiently administered by a single provincial government.
However, the officials who worked out the plan had also other ends in view. They hoped to stem the rising tide of nationalism in Bengal, considered at the time to be the nerve centre of Indian Nationalism.
Risely, Home Secretary to the Government of India, wrote in an official note on 6 December 1904: ‘Bengal United is a power. Bengal divided will pull in several different ways. That is what the Congress leaders feel: their apprehensions are perfectly correct and they form one of the great merit of the scheme… one of our main objects is to split up and thereby to weaken a solid body of opponents to our rule.’
Above statement clearly establishes that considerations other than administrative convenience led to the partition of Bengal. More over, administrative efficiency could have been better secured by separating the Hindi speaking Bihar and the Oriya speaking orissa from the Bengali speaking part of the province.
The real reason that led to the partition of Bengal was the British attempt to weaken the Indian nationalism. Bengal at that time was the most educated and prosperous province of India. Most of the national leaders came from Bengal. Bengal united was a threat to the British rule in India, thus they partitioned it. Bengal was the becoming the centre of militant nationalism, and it was the most informed province about the true nature of British rule. Above all one of the motives that led to the partition of Bengal was to divide the province on religious grounds: Muslim dominated East Bengal and Assam and Hindu dominated Rest of Bengal.
Thus what actually led to the partition of Bengal was the British deliberate attempt to ‘divide and rule.’