During the difficult years that preceded the British handover of Hong Kong to China, the Chinese government's intense antipathy to opium and the still fresh memories of the evil that buccaneering 18th-century Britain inflicted on China and Hong Kong added an extra emotional charge to what, anyway, was a most complicated transition. Without opium there would have been no Hong Kong. The British only acquired it because of the Opium wars, and the city's early economic success was built on the opium trade.
It was the British who fed the Chinese propensity for opium. Historians point out that the Chinese would have found it elsewhere, even grown some of it themselves. But the truth is the Indian-grown opium was the brand the Chinese smokers savoured and the British East India Company marketed it with commercial elan.
Today mainland authorities regard opium as a singularly bad thing. But in Hong Kong there is a public debate, shades of grey, layers of complexity, both historically and currently. The study of opium becomes as complicated as an addict's dreams and the solutions to abuse as tortuous as cold turkey.
It was the communist revolution that expunged opium. Mao Zedong , with his political apparatus that reached into every hamlet and home, was able to lay the beast low as he repressed so many attributes of human nature, both good and bad.
It was a mixture of carrot and stick. Addicts were not condemned but offered medical help and rehabilitation. But those who were unco-operative were sent to labour camps or imprisoned. Dealers were summarily executed, often without trial.
China was clean for 40 years, until the demise of Mao. Gradually opium has returned. Now the mainland is one of the world's most important opium growers. Although it still regularly executes drug traffickers, demand in its freewheeling economic society finds willing suppliers prepared to take the risk. As a Chinese proverb puts it: 'If you open the window sunlight comes in, but so do mosquitoes.'
Government attitudes on the mainland have not changed. But the black market is a match for government, as it is almost everywhere.
