Between which two countries was the "First Opium War"?

The "First Opium War", also known the Anglo-Chinese War, was a series of military engagements fought between the United Kingdom and the Qing dynasty of China over diplomatic relations, trade, and the administration of justice in China.

In the 17th and 18th centuries, the demand for Chinese goods (particularly silk, porcelain, and tea) in Europe created a trade imbalance between Qing Imperial China and Great Britain. European silver flowed into China through the Canton System, which confined incoming foreign trade to the city of Canton. To counter this imbalance, the British East India Company began to grow opium in India, and smuggled it into China illegally. The influx of narcotics reversed the Chinese trade surplus, drained the economy of silver, etc. In 1839, the Emperor, rejecting proposals to legalize and tax opium, appointed viceroy Lin Zexu to halt the opium trade completely. Lin wrote to Queen Victoria an open letter in an appeal to her moral responsibility to stop the opium trade. When he failed to get a response, he initially attempted to get foreign companies to forfeit their opium stores in exchange for tea, but this failed too. He confiscated all supplies from western merchants and ordered a blockade of foreign ships to get them to surrender their opium supply. The British government responded by dispatching a military force to China and in the ensuing conflict, the Royal Navy used its naval and gunnery power to inflict a series of defeats on the Chinese Empire.