Leading article: In today's China, not all that glisters is gold

The Beijing Olympics begin today with what China has promised will be an opening ceremony without precedent in scale and splendour. You may even be watching it as you read this. Ever since the city was controversially awarded the 2008 Games, the Chinese authorities have done their utmost to ensure that they would be a model of their kind – a showcase, not just for Beijing but for the new China.

There was no question that the venues would be completed in good time. There was no question either that they would be better and more distinctive than those hosted by other cities in recent years. In the quest for efficiency, the Olympics juggernaut flattened all before it, including some of the most picturesque quarters of old Beijing. Nor was the human factor left to chance; even ordinary members of this enormous city's population were drilled in acceptable ways to meet and greet.

For the next two weeks China will be open to the world – and yet not open. It will be open in the sense that many foreign dignitaries, but fewer than expected foreign tourists and sports-lovers, will be enjoying its lavish hospitality. It will be more open than perhaps the authorities had calculated: while many restrictions on foreign journalists were lifted for the whole of the Olympic year, censorship of the internet has now been partially lifted at the insistence of visiting reporters. Computer-literate Chinese with a smattering of a foreign language will have access, suddenly, to an infinitely wider world. And protest is being accommodated, within limits.

The face Beijing turns to the world will be one that encourages us to believe not just that China is a rising global power, but that its rise is a thoroughly benign development that presents no threat to anyone else. But the impression of openness – like so many other impressions China has been trying of late to foster – obscures a more complex, and often darker, reality.

The suppression of disturbances in Tibet earlier this year conveyed the message that Han domination of Tibet is non-negotiable. The British and other campaigners who hoisted a "Free Tibet" banner at the Bird's Nest stadium were summarily deported – a milder punishment than they might have faced in non-Olympic times. A bomb attack in Xinjiang has brought a predictable security crackdown. As for openness, access to certain Chinese-language internet sites are still blocked; and fraternisation between Chinese and visitors will be heavily circumscribed by security levels in Beijing. The special forces thugs sent to accompany the Olympic torch on its progress across continents afforded a glimpse of the methods a sensitive state employs.

China is still a one-party state, albeit a more relaxed and responsive one than 20 years ago. Dissent of many hues is punished, be it political, religious or ethical. Parents who protested about corruption after their children were killed in the Sichuan earthquake are among the latest victims. China sustains a Gulag every bit as extensive as that in the former Soviet Union.

Today's China has one of the fastest growing economies in the world; millions have escaped grinding poverty. It is undoubtedly an emerging superpower. But it is not, by any recognisable definition, a democracy, nor does it even hint of becoming one. This should put us on our guard. Between now and the closing ceremony on 24 August, Beijing has one aim above all other: to banish the 19-year-old ghosts of Tiananmen Square and replace them with the smiling visage of universal sportsmanship. Let's enjoy the Games, but also look beyond what China wants us to see.