China has unequalled armed capacity to suppress dissent, and has had no compunction about using it - least of all in Tibet, a land whose spirit China's rulers have been determined to break for more than 50 years. Well before this week's initially peaceable, and extraordinarily brave, marches by Tibetan monks to mark the 49th anniversary of the Dalai Lama's flight into exile, China's security forces had been put on high alert for Tibetan protests linked to the Beijing Olympics, explicitly instructed by Communist Party officials to do whatever it took “to bring those with ulterior motives under control”.

By swiftly barring the monks' paths and bundling their leaders into police vehicles, surrounding or occupying Lhasa's principal monasteries and saturating the city with armed enforcers, Beijing's strategy was to stifle the protest at birth. It backfired. Outraged Tibetans rushed to the monks' defence, throwing stones and bars at police, torching markets, cars and shops and venting their anger on keenly resented Han Chinese merchants. Parts of Lhasa were set ablaze, the wounded filled hospitals, and revolt rapidly spread across Tibet and to former Tibetan territories annexed by China half a century ago.

Beijing has an uprising on its hands as serious, more widespread and, above all, more keenly watched by the world than the last big Tibetan revolts in 1989, which were brutally suppressed by the man who is now President and party general secretary of China, Hu Jintao. Mr Hu put down that uprising with mass arrests, torture and 13 months of martial law. Only last week, he emphasised to the leadership of Tibet's Communist Party that “Tibet's stability has to do with the entire country's stability.” There are unconfirmed reports of military deployments. But breaking heads this time could cost China dear.

The crushing of Tibet is a human rights cause about which people across the world care passionately. China's clumsy vilification of the Dalai Lama, a great spiritual leader manifestly committed to peace and tolerance, has made bad worse.

People who will never get near the Roof of the World care about the fate of the Tibetans - and a bitter fate it has been. When Mao Zedong marched Chinese troops in after the revolution, he pledged to respect Tibetan traditions and its god-king, the Dalai Lama. He broke those undertakings, and, after crushing the Tibetan uprising of 1959, annexed nearly half the country outright, subjecting the remaining Tibetan heartland to heavy-handed military and political occupation. Tibetan suffering has been extreme. In the 1950s, collectivisation brought famines; in the 1960s, more than 6,000 Buddhist monasteries, the country's spiritual and cultural heart, were ripped apart in the Cultural Revolution; and China has deliberately set out to destroy Tibetan identity by swamping Tibet with Han Chinese settlers, who get the best jobs and housing, and treat Tibetans like second-class citizens. They live, as the Dalai Lama said in his 49th anniversary speech this month, “in a state of constant fear, intimidation and suspicion”; and repression has got worse, not better, mocking the Dalai Lama's unavailing efforts to reason with Beijing.

China's instinct may be to use the Olympics to justify tough “security measures”. The last thing Beijing wants is, by acting gently, to embolden other dissidents. But if China comes near the brutality of the Burmese junta, that would give rise to disgust so strong that it could defeat the spirit of the Games, even if it did not douse the flame itself. Bernard Kouchner, the French Foreign Minister, hinted as much yesterday, pointedly linking the Olympic spirit to “Tibetan aspiration, which China has to take into account”. Beijing's protests that the world has no business politicising the Olympics will do no good. Already, China invites ridicule by its pathetic efforts to accuse the Dalai Lama of sabotaging the Games. Western leaders must hold China strongly to account. All heads of government should also abandon their cowardice about receiving the Dalai Lama, not just as a man of religion and Nobel laureate but as Tibet's legitimate leader. He is due in London this May. Gordon Brown should announce forthwith that the red carpet awaits him.