What was the motive of Lord Wellesley to introduced the system of Subsidiary Alliance?

Wellesley’s aims were expansionism and imperialism. He wan­ted to expand the British dominions in India to such an extent that it should become the sovereign power in India. His expansionist mind would not remain content with British remaining one of the powers in India, as such he set himself to the task of converting India into an empire of Britain. Another aim, which was ancillary to his main objective, was removal of French influence from India and to make possibility of French territorial expansion of India impossible.