The Subsidiary Alliance was a diplomatic strategy used by Lord Wellesley to consolidate British control over India. The Nawab of Awadh, like other Indian rulers, was forced to accept the presence of a British army within his state. He had to bear the cost of the army's maintenance, and in return, the British offered military protection. Furthermore, the Nawab was prohibited from having any diplomatic relations with other powers without British consent. This policy significantly reduced the Nawab's autonomy and led to the annexation of Awadh when the Nawab failed to meet the British conditions.