Since June 2019 Hong Kong has been – first figuratively, then literally – on fire. What began as a “summer of discontent” has become a running street battle, marked by acts of violence by both police and protesters. In November, Hong Kong’s university campuses were combat zones, bristling with makeshift barricades and petrol bombs; police responded with threats of using live ammunition.

The protests had an immediate trigger: a controversial bill proposed by the chief executive, Carrie Lam, that would permit extradition from HK to the People’s Republic of China. Activists in HK fiercely opposed it because they feared it would break down a barrier between the legal systems of the PRC and HK, making it possible for the mainland – which has become increasingly politically repressive over the past seven years – to extradite political activists and dissidents into China’s opaque and Communist party-dominated legal system. Keeping the two systems separate for at least 50 years was a keynote of basic law governing the return of HK to mainland China in 1997.

But it’s impossible to understand the vehemence of current rebellion without highlighting a string of longer-term grievances that have led to this crisis. Since HK’s return to mainland government control in 1997, the island has simmered with anxiety about its government’s relationship with Beijing. This unease has periodically erupted into mass demonstrations when the administration has attempted to pass legislation that would explicitly tighten Beijing’s grip on local affairs.

In 2003 (when the then chief executive Tung Chee-hwa tried to introduce an anti-sedition law extending mainland political control) and 2014 (when Beijing stalled attempts to democratise selection of HK’s chief executive) hundreds of thousands took to the streets. Unease has intensified over the past six years, following the abduction by mainland agents of local publishers of Chinese political exposés. Frustration at this string of encroachments on Hong Kong’s autonomy led to the unprecedented violence of 2019. One piece of anti-government graffiti said: “It was YOU who taught us that peaceful protest doesn’t work!”

Carrie Lam takes her oath in front of Chinese President Xi Jinping in Hong Kong, July 2017. Photograph: Bobby Yip/Reuters

Joshua Wong’s memoir, Unfree Speech, weaves an activist’s biography through this contemporary history. Wong was born in 1996, on the eve of the handover. In his view, HK’s first decade after returning to Chinese rule “was nothing short of catastrophic”. Its economy was rocked in turn by the 1997 financial crisis, the 2002-03 Sars epidemic and a burst housing bubble. GDP shrank, unemployment rose.

A precociously politicised child, the 12-year-old Wong blamed these failures on HK’s dysfunctionally partial democracy – a product of drawn-out negotiations between the departing British and the incoming Chinese Communist party. The chief executive is selected by a small committee dominated by mainland loyalists. Only half the legislative council (LegCo, Hong Kong’s parliament) is elected through open democratic vote. The other half is chosen by trade and special interest groups allied with Beijing and who vote “at the bidding of the government”. Wong concluded that “Everything that’s wrong with Hong Kong was attributable to a single culprit: our unaccountable government and the lopsided electoral system that created and facilitates it.”

In 2012, Wong’s first campaign fought a government attempt to introduce “moral and national education” into local schools, a policy that he and many other school students saw as stealth communist brainwashing. Wong, by then 15, learnt how to draw tens of thousands of citizens to rallies, to collaborate with other civil society groups and to generate viral speeches and interviews. This was, he argues, a turning point in post-handover history: the emergence of effective, dynamic youth politics. Where the adults have failed, “young people will take up the mantle … Politics is no longer an exclusive sport for grey-haired politicians and lifelong bureaucrats”.From here, Wong plunged into 2014’s pro-democracy protests (the “umbrella movement”), during which he was arrested for civil disobedience. Although the movement failed to deliver clear results, Wong argues that “the sweeping political awakening and civic engagement it brought about are indisputable [in giving] Hong Kongers, especially my generation, new confidence to challenge Communist China”.

By this point, he had become an international celebrity: “the face of protest”, as Time magazine dubbed him. His memoir appealingly backs away from individual grandstanding, though, and he is consistently modest about his own achievements: “the true heroes” of his political story “are the amazing people of Hong Kong”. In 2016, perhaps the high point of Wong’s career, his pro-self-determination party Demosisto secured its first seat at LegCo. But since then he and his fellow activists have increasingly fallen victim to the government’s attritional strategy of “lawfare”, which stifles oppositional activism by doling out punitive sentences for protest. Two months shy of his 21st birthday, Wong and two of his closest comrades were sentenced to up to eight months’ imprisonment for participating in the umbrella movement three years previously. This was part of a broader pattern of the government’s “relentless pursuit of political activists through the criminal justice system” – and helps explain why the 2019 extradition bill lit the touchpaper of public anger.

Riot police during an anti-government protest in Hong Kong, January 2020. Photograph: Anadolu Agency via Getty Images

Wong’s sense of mission – his dedication to fighting for HK’s long-term political future – stems substantially from his upbringing as a devout Christian: “God … put me on this world for a reason.” But the book is also careful to reveal Wong’s boyish side. His recollections are conspicuously studded with references to the superhero cartoons and films that seem to dominate his imagination. “I lived the life of Peter Parker,” he recalls of his 2012 campaign. “Like Spider-Man’s alter ego, I went to class during the day and rushed out to fight evil after school.” “If Carrie Lam resembled Darth Vader,” he analogises about the architect of the infamous extradition bill, “the Hong Kong Police Force would be the armour-clad, blaster-brandishing stormtroopers terrorising villagers across the galaxy.”

True to this Star Wars frame of reference, the book posits a Manichean opposition between the interests of democratic HK and mainland China, charting the ambition of the increasingly repressive PRC government to use its international “sharp power” to export its “brand of one-party rule in Asia and beyond”. There is “a new cold war … brewing between China and the rest of the democratic world, and Hong Kong is holding the line in one of its first battles”.

There are good reasons for his apprehension. He experienced the long arm of Chinese influence when in 2016 he was detained without legal redress in Bangkok: “Thailand is just like China!” an official said. But activists in HK should be wary of demonising China and its people – not least because finding common cause with mainlanders also disadvantaged by China’s unaccountable one-party system and inequalities is key to the long-term vigour of the democracy movement. This aspiration to solidarity is, admittedly, exceptionally difficult to realise, as coverage of HK within mainland media has been subject to stringent control. Official media has hammered home the message that the protests are an irrational explosion of violence, omitting the serious political causes in play.

At present, Hong Kong is politically paralysed. The protesters seem determined to continue, but the HK and Beijing governments show no sign of being willing to agree to citizens’ demands. The current uncertainty makes it hard to measure Wong’s long-term impact or legacy. Nonetheless, his tenacious dynamism shines through Unfree Speech: a guide to mobilising for democracy and representation in and far beyond Hong Kong.

• Unfree Speech is published by WH Allen (RRP £9.99). To order a copy go to guardianbookshop.com. Free Uk p&p over £15.