For the past week, at home in London, I have been living in the Hong Kong time zone. At night I watch live feeds of pro-democracy protesters waking at dawn in an occupied street of Admiralty; the next morning, I turn my computer back on and see the same street filled with a swollen river of humanity chanting their political demands in unison and holding up luminous mobile phones to the night sky. These riveting scenes have filled me with profound admiration for the courage of the protesters, and renewed hope for democracy in both Hong Kong and mainland China. Whatever the eventual outcome of this movement, it marks a historic turning point. It is the largest and most concerted act of defiance against China’s totalitarian regime for the last 25 years.

As a Chinese exile and former resident of Hong Kong (I lived there for 10 years after my books were banned in China), these protests are particularly poignant for me. When the protesters opened their umbrellas against a torrential downpour four days ago, my mind flashed back to the rain-soaked night of 30 June 1997, when fellow artists and writers gathered in my studio in Sai Ying Pun to lament the territory’s handover to Chinese rule. As the rain lashed down outside my windows, the long-haired activist and director Augustine Mok performed a piece of indoor street theatre; Pan Xinglei, recently imprisoned for splattering paint over a statue of Queen Victoria in Causeway Bay, painted his own face red; and the French band La Souris Déglinguée sang Hong-Kong and Quartier Libre.

At midnight, after the union jack was lowered and the Chinese national flag was ceremoniously raised to the strains of communist martial music, we braved the deluge and joined the crowds outside the legislative council protesting against the termination of Hong Kong’s fledgling democracy. There was a heady mixture of excitement, despair and foreboding that night, but beneath it all a deep sense of betrayal.

Seventeen years later, this sense of betrayal is still strong, and it is the desire to assert their independence and regain their dignity that has driven Hong Kong’s people on to the streets.

When I saw the images last weekend of riot police in helmets and gas masks shooting canisters of teargas into crowds of peaceful, unarmed students, my thoughts travelled further back, to 4 June 1989, when 200,000 armed soldiers advanced on Beijing and attacked peaceful protesters with machine guns, bayonets, batons and teargas, leaving in their wake unknown numbers of corpses crushed by their armoured tanks.

Twenty-five years later it seemed that these crushed corpses had at last returned to life in the streets of Hong Kong. The echoes were everywhere: the students’ fervent desire for democracy, their restraint and calm order; even the earnest, adolescent faces of the leaders, Joshua Wong and Agnes Chow, recalled those of the Tiananmen leaders, Wang Dan and Chai Ling. One difference, however, was that these students were holding umbrellas they had brought to protect themselves from the rain, but were now using as ad hoc, pitifully inadequate shields against clouds of teargas and pepper spray.

Those umbrellas reminded me of a torrential downpour in the spring of 1989 that for a few hours washed the crowds of protesters and hunger strikers from Tiananmen Square. Gazing out at the megaphones and red and black banners floating in the flooded and deserted square, I spotted a contingent of students from Hong Kong arriving with truckloads of donated tents and sleeping bags. The support they offered, both material and psychological, was invaluable to the Beijing Democracy Movement.

Many of the university and high-school students filling the streets of Hong Kong today were not alive in 1989, or even during the handover of 1997, but they have a deeper understanding of China’s recent past than most of their contemporaries in the mainland.

They are descendants of refugees from China’s famines and political upheavals; they have grown up witnessing the mass candlelit vigils held in Victoria Park every year to commemorate the Tiananmen massacre. They have witnessed the gradual erosion of the autonomy and liberties guaranteed by the “one country, two systems” principle of the 1997 Basic Law; attempts to brainwash children with a Beijing-formulated moral and national education; creeping self-censorship in the media; suggestions that Hong Kong judges be chosen for their patriotism; and a meat-cleaver attack in broad daylight on the editor of the liberal Ming Pao newspaper.

Although motivated by a multitude of discontents, the strength of the “umbrella revolution” lies in its narrow focus on one demand: genuine universal suffrage and, more precisely, the scrapping of the Chinese government’s decision that a pro-Beijing committee vet the candidates allowed to run for Hong Kong’s next chief executive.

The Chinese authorities have condemned the protests as illegal acts, and stated that true democracy in Hong Kong would lead to social chaos. But it is clear the opposite is true: it is the refusal to grant genuine electoral freedom that is the cause of the current uprising. Rejecting demands to resign the chief executive, CY Leung, has promised the students talks with his second-in-command, no doubt hoping that the protests will peter out before he is forced to make any concessions.

The attacks launched on the protesters since then by organised mobs are both disturbing and predictable. But the Occupy movement must not be cowed by thuggery, and should continue to push for reform. For it is hard to imagine a people more equipped for democracy than the restrained, educated citizens of Hong Kong. These are protesters who, while calling for freedom, hand out biscuits and bottles of water, shield policemen from the rain and hang up notices apologising to local residents for “any inconvenience caused”.

The fact that the British colonialists failed to grant Hong Kong any democracy until the last years of their rule is no excuse for Beijing to renege on its promise to grant the region universal suffrage in 2017, in line with article 45 of the Basic Law. Western governments, so keen to clamp down on undemocratic regimes in the rest of the world, should express unequivocal support for the protesters’ demand for free and fair elections, and publicly condemn the authorities’ unjustified use of force. Having delivered their former subjects into the hands of a communist dictatorship, Britain has a particular moral duty to ensure that their basic rights, safety and autonomy are protected.

The people of Hong Kong should take heart, and realise that although each one of them may be but a single drop of rain, they converged this week to become an unstoppable river of democracy that coursed through Admiralty, Causeway Bay and Mongkok. The river will flow again, despite efforts to block it, and will one day, perhaps this year or many years from now, surge across the border all the way to Tiananmen Square.

Translated by Flora Drew