Opium Wars

The  were fought in China prior to the 1860s, against the British Empire and French Empire on one side (PROSE: The Eleventh Tiger) and the Chinese Empire on the other. (PROSE: The Nightmare Fair, AUDIO: The Nightmare Fair)

Background
China became the centre of Britain's highly profitable opium trade during the 18th and 19th centuries. However, there was much smuggling and corruption within the trade, and many members of the Chinese population also became addicted to the drug, leading them and their families to suffer. In December 1800, as the trade was overseen by Roderick Upcott, the Chinese Emperor intended to stamp out these problems. His Chief Astrologer sought to achieve this by targeting the British Trade Concession in Canton. With the Chief Astrologer's encouragement and assistance, riots broke out in Canton among the local population against the Concession. Other trade nations with Chinese interests, such as Portugal and France, also prepared for trouble. (PROSE: Foreign Devils)

The wars
The British Fleet bombarded some Chinese coastal towns. (PROSE: The Nightmare Fair, AUDIO: The Nightmare Fair) British and French forces attacked the mainland, capturing ancient temples and using them as watchtowers. (PROSE: The Eleventh Tiger)

Aftermath
The British and French continued to use occupied temples as watchtowers after the wars. The main garrison of the British Army was stationed on Xamian Island. Individuals among China's population, such as Wong Fei-Hung, felt disappointment and shame for China's defeat. (PROSE: The Eleventh Tiger) However, the Sixth Doctor spoke of the outcome as a positive one. He claimed Imperial China was corrupt which made it all too attractive a playing field for beings such as the Celestial Toymaker, whom the Doctor accused of preferring an outcome where the Empire continued to exist for thousands more years. (PROSE: The Nightmare Fair, AUDIO: The Nightmare Fair) The last remnants of the ailing Empire were swept away in 1911 when Pu Yi was ousted by Sun Yat Sen's Nationalists and China became a republic. (PROSE: The Shadow of Weng-Chiang)

Behind the scenes
There were two Opium Wars. The (1839-1842) was primarily a British and Chinese affair. The (1856-1860) also saw the involvement of the French and the limited participation of the United States. Given this, Barbara Wright and Wong Fei-Hung's references to the Opium Wars in The Eleventh Tiger likely refer mostly to the Second.