Your guide to the Opium Wars

As well as being used as a medicine, it has also been a popular recreational substance. By the 1830s, millions of Chinese were hooked on opium, causing significant damage to the health and productivity of the nation.

Much of the opium the Chinese were smoking had been imported by the British.

• Where does the story of opium begin?

Why were the British exporting the drug to China?

At this time there was great demand in Britain for Chinese products such as porcelain and tea, but the Chinese did not want to trade British goods in return. Instead they demanded to be paid in silver. Rather than allow the country’s silver reserves to be drained, some enterprising British merchants adopted a different solution.

They took opium grown in India (which was then effectively under British control) and imported it into China, insisting on being paid for the drug in silver, which could be used to purchase Chinese products.

Although importing opium was illegal, corrupt Chinese officials allowed it to take place on a vast scale.

How did this lead to war?

In 1839 the Chinese government decided to crack down on the smuggling. It ordered the seizure of large quantities of opium from British merchants in the Chinese port of Canton, which was the only part of the country where Europeans were allowed to trade.

The outraged merchants lobbied the British government for assistance and on this occasion they found a ready audience. Britain had long hoped to increase its influence in China. This seemed like a perfect opportunity to achieve that goal.

A British naval fleet arrived in June 1840, attacking along the Chinese coast. With their inferior military technology, the Chinese were no match for the British and, after a series of military defeats, they agreed to sign humiliating peace terms.

• The long and unhappy history of trade between China and the west

These stipulated that China pay a large fine to Britain, open up five more ports to foreign trade, give the British a 99-year lease on the island of Hong Kong and offer British citizens special legal rights in China.

In later years, China referred to this settlement as the ‘Unequal Treaty’.

So that was the first Opium War. How did the second one come about?

With China humiliated and Britain seeking further gains, the situation remained tense.

The spark for the second conflict occurred in 1856 when Chinese officers searched a Chinese owned (but British registered) ship and lowered the British flag. In response to this affront, the British once again dispatched a military expedition, and this time they were joined by the French, who also had aspirations in China and were protesting about the murder of one of their missionaries in the country.

As before, the European powers were too strong for the Chinese. A peace agreement was reached in 1858 but, the following year, China broke off the deal. This led, in 1860, to the arrival of an even larger Anglo-French force, which stormed Beijing.

By October, the Chinese had been forced to accept British and French terms that included the right of foreign powers to keep diplomats in Beijing and the legalising of the opium trade.

• Hitler's drug addiction

What was the legacy of the Opium Wars?

In Britain they became something of a footnote in history, although the country did retain control of Hong Kong until 1997. For China the impact was more dramatic.

The military defeats weakened the Qing dynasty that was ruling the country, while the new treaties meant that China was opened up to more foreign influence.

In recent years this has been described as the start of a century of ‘national humiliation’ by foreigners that some argue only came to an end with the seizure of power by the Communist party in 1949.

This article was originally published in the August 2014 issue of BBC History Revealed magazine