This week police in Hong Kong fired tear gas and water cannon at protesters rallying against Beijing’s tightening grip on what had been one of Asia’s freest cities. A journalist and historian explains that the seeds of the takeover were laid in legislation adopted in China 30 years ago

The blue book on my desk, embossed in red and gold with the insignia of the People’s Republic of China, is a hallowed text for Hong Kong. It is the Basic Law under which the city has been governed since it was handed back by Britain to China in 1997. It is as solemn a document as the language of Marxism-Leninism permits. Perhaps that is why so few people have actually read it.
The Law is at the core of the latest phase in a long conflict between the people of Hong Kong, who wish to rule themselves, and the Chinese government, which means to draw their troublesome city into the full embrace of the motherland.

It is a different document from the Joint Declaration signed by Britain and China in 1984, which is a short, in parts creatively ambiguous, statement of principles, most commonly and misleadingly remembered as a guarantee that Hong Kong could keep its rights and freedoms for 50 years after the handover. The Basic Law is a purely Chinese document. Its clauses grant practically unlimited powers to the Beijing government in the event of a state of war or “turmoil within Hong Kong … which endangers national unity or security”, allowing it to declare a state of emergency.