William Ewart Gladstone (29 December 1809 - 19 May 1898) was a British statesman and Liberal politician. In a career lasting over 60 years, he served for 12 years as Prime Minister of the United Kingdom, spread over four non-consecutive terms beginning in 1868 and ending in 1894. He also served as Chancellor of the Exchequer four times, serving over 12 years.

The opium trade incurred intense opposition from the later British Prime Minister William Ewart Gladstone. As a member of Parliament, Gladstone called it "most infamous and atrocious", referring to the opium trade between China and British India in particular. Gladstone was fiercely against both of the Opium Wars, was ardently opposed to the British trade in opium to China, and denounced British violence against Chinese. Gladstone lambasted it as "Palmerston's Opium War" and said that he felt "in dread of the judgments of God upon England for our national iniquity towards China" in May 1840. Gladstone made a famous speech in Parliament against the First Opium War, criticising it as "a war more unjust in its origin, a war more calculated in its progress to cover this country with permanent disgrace". His hostility to opium stemmed from the effects of the drug upon his sister Helen. Due to his disgust at the First Opium War, brought on by Lord Palmerston, Gladstone was initially reluctant to join the government of Robert Peel, but did so in 1841.