Why did the british empire insist on their right to trade opium with china?

There was a huge demand in Europe for chinese products such as tea, pottery, silk, porcelain. But the British really didn't have anything that China wanted so they had to trade gold and silver for the products. When the Chinese people became addicted to the opium, it meant that Britian could now trade that for the products they wanted.

The common sense pamphlet i think