Britain regulated froeign trading with china as a result of the Treaty of Nanjing.
The Treaty of Nanking was a peace treaty which culminated the First Opium War (1839–1842) between the United Kingdom and the Qing dynasty of China on 29 August 1842.
The primary objective of the treaty was to change the framework of foreign trade imposed by the Canton System, which had been in force since 1760.