When the Taxman Blinked: How Opium Went From Profit to Prohibition

Opium wasn’t always a criminal word in Britain. For most of the 19th century it was a normal, legal commodity: sold in patent medicines, taken as laudanum, and treated as an everyday remedy. The state’s first instinct was not prohibition; it was trade.

That instinct is exposed by the Opium Wars. Britain was smuggling opium into China from British-controlled India, and when the Chinese authorities moved to suppress the drug, the conflict escalated into war. It wasn’t framed as a public-health rescue mission. It was an imperial dispute over commerce, access, and profits.

Domestically, Britain’s approach followed the familiar pattern of a profitable harm: professionalise it, don’t kill it. The Pharmacy Act 1868 did not ban opium; it tightened who could sell “poisons” and dangerous drugs, pushing supply into the hands of registered chemists. You could still buy opium preparations, but the market was being cleaned up—more control, less scandal.

By the 1890s, pressure to end the opium regime in India and the wider trade had become politically awkward. The government’s response was classic Westminster heat■management: commission the problem. The Royal Commission on Opium (1893–1895) examined the issue and ultimately defended the existing system, blunting the moral campaign against the trade. Modern histories of UK medicines regulation note bluntly that opium revenue was seen as essential to financing the Government of India.

So what changed? Not a sudden burst of compassion. The world changed around Britain. International pressure for narcotics control hardened. The Hague International Opium Convention was signed in 1912 by the UK and others, and after the First World War the post■war settlement made adherence far harder to avoid. Britain could no longer treat opium as “our profitable exception” without diplomatic cost.

Then the law followed the new incentives. The Dangerous Drugs Act 1920 tightened controls over opium and other drugs, shifting Britain toward a permits-and-prescriptions model that criminalised what had long been routine. The government didn’t lose its taste for revenue; it lost the political conditions that made opium revenue easy to defend.

The lesson isn’t that Britain uniquely sinned in the past. The lesson is how state morality works in practice. When a harmful commodity feeds the machine, government language turns soft: “regulation”, “custom”, “personal choice”. When the optics turn, or the diplomacy bites, the same commodity becomes a “menace” and gets a crackdown.

Opium didn’t become illegal because the state discovered virtue. It became illegal when the balance sheet and the headlines stopped cooperating. And once the state had a cleaner story to tell—public safety, international duty, modern standards—it could criminalise yesterday’s profit while keeping the habit that never changes: finding the next thing to tax.