To what extent is this statment true? "There were extensive network of relationship with local tribal leaders to establish economic opportunities in the British Empire."
This statement is quite accurate as far as it goes, but it could go further. The British actually created these networks of relationships not just for economic opportunities, but also as a way of establishing, spreading, and maintaining control of areas in their empire.
The British were never going to bring enough English people to run their entire empire. Therefore, they needed to make connections with local people who could provide the labor needed to enrich the British. In order to do so, the British typically used local leaders who were already in place so they would not have to set up new systems that might not even work.
As they did so, the British benefited in two ways. First, they got access to the wealth created by the people. Second, they came to have more and more power over the local leaders who depended on the British for their power and prestige. This allowed the British Empire to spread and to run efficiently.