* British trade expansion in China. In the 18th and 19th centuries, the British East India Company established a thriving trade relationship with China. The company exported cotton and opium to China and imported tea, silk, and porcelain. Britain's appetite for tea resulted in a trade deficit with China, as the British were forced to pay for their imports with silver. As British opium sales grew, the volume of opium imported into China steadily increased, causing serious addiction and social problems.
* Attempts by the Chinese government to suppress opium smuggling. The Qing government recognized and banned opium imports and consumption as early as 1729. However, the trade was highly profitable for British merchants and Chinese merchants who collaborated with them, and opium smuggling continued. The Chinese government repeatedly tried to crack down on the trade, but its efforts were often ineffective and corrupt officials were often bribed to look the other way.
* Conflict over diplomatic protocol and extraterritoriality. In addition to the opium trade, tensions between Britain and China were exacerbated by a number of other issues. Britain insisted on equal diplomatic treatment with China, but the Qing government refused to treat British representatives as equals and refused to allow them to live in Beijing. Britain also sought extraterritoriality for its citizens, meaning that they would be subject to British laws rather than Chinese laws.
* Perceived arrogance of the British. British representatives and merchants often acted in an arrogant and disrespectful manner towards Chinese officials and citizens, fueling resentment against foreigners.
Opium Wars (1839-1842 and 1856-1860)
The culmination of these tensions was two wars between Britain and China, known as the Opium Wars. The First Opium War (1839-1842) began when Chinese authorities seized and destroyed British opium ships at the port of Canton (modern-day Guangzhou). Britain responded by sending a naval force to attack Chinese coastal cities and eventually captured the island of Hong Kong.
The Treaty of Nanjing, which ended the First Opium War, was signed in 1842. The treaty gave Britain control of Hong Kong, opened five Chinese ports to foreign trade, and granted extraterritoriality for British citizens in China. The treaty also imposed a large indemnity on China and forced the Chinese government to legalize the opium trade.
The Second Opium War (1856-1860) was fought over similar issues and ended with another British victory. The Treaty of Tientsin (1858), which ended the Second Opium War, gave Britain further concessions, including the opening of more Chinese ports to foreign trade and the legalization of opium cultivation in China.