Answer:
The First Opium War was fought between the British East India Company and the Qing Dynasty of China between 1839-1842 with the aim of forcing China to allow free trade, especially opium. Britain called for the opening of the opium trade, while China's imperial government tried to ban it.
English traders were expelled from China and upon arrival in London lodged a complaint with the British government, which decided to attack China with its powerful armada to force the Chinese to buy opium grown in British India.