It all looked final: the torrential rain, the bowed head of the last governor, Chris Patten, the illustrious onlookers Prince Charles and President Jiang Zemin. The British flag was lowered for the last time on Hong Kong at the end of June 1997. After over a decade of fractious negotiations, one of the few remaining areas of Britain’s colonial enterprise was wrapped up for good.

The handback arrangement stipulated that the People’s Republic of China would maintain Hong Kong under a unique “One country, two systems” rule where the city would be allowed a high degree of autonomy for 50 years. The UK committed to producing six-monthly parliamentary reports detailing the state of play under the new regime. Both sides shared undemanding obligations, leaving Hong Kong free to forget the past and, broadly speaking, move on.

For the first decade, Hong Kong maintained its unique position and distinctiveness. There were occasional irritants for Beijing – large pro-democracy protests in 2003 and the annual commemoration of Tiananmen Square – but during the era of the Chinese President Hu Jintao (2002-2012), China was too busy getting rich to bother about much else. Hong Kong’s international finance centre was a boon to these aims.

Once Xi Jinping became general secretary, though, China became more confident and nationalistic. The world outside of China became less sure of itself, knocked sideways by the 2008 financial crisis. The UK, too, has been distracted by matters closer to home. In an era of internet connectivity and international flights, Hong Kong has grown more, not less, distant from the lives of the average British person. Bar its history, the UK has little to do with the former colony. The question today is what, if anything, this connection obliges the UK to do in the face of Hong Kong’s continued protests.

The world may see China's response to the recent protests as yet more evidence of its obliviousness to what others think, stewing in irritation and letting off sharp and intemperate diplomatic comments. Carrie Lam, Hong Kong’s benighted chief executive, has stated the city cannot extradite a local wanted for murder in Taiwan. Antagonistic relations between China and Taiwan mean that Hong Kong does not recognise the island’s status, and that Taiwan will ultimately need a treaty with the mainland in order to secure an extradition. Speculation suggests that Beijing wants to use the current extradition controversy to rope in Taiwan. Taiwan, meanwhile, has said resolutely that it won’t accept any request for extradition that treats the country as a part of China.

Hong Kong’s executive faces a huge public backlash, an increasingly politicised and angry young population, and a man who is suspected of committing murder who could likely walk free later this year unless something changes. All of this is in the name of the city remaining a pawn in Beijing’s larger strategic aims. The current problems prove that on the issue of Hong Kong, history is definitely not resolved for Beijing. And when London speaks about the matter, it attracts opprobrium.

Questions of the UK's obligation would never have arisen had the former colony continued on the course that many expected: a placid country where people were more concerned with wealth than political revolt. The protests have challenged this narrative and thrown light on Hong Kong’s troubled situation. Attempts to find a new means for voting in a chief executive in 2014 were botched. Signs of mainland interference in the affairs of the city are clear, from the kidnapped booksellers in 2015 to the disappearance of business people from China.

For Hong Kong’s younger generations, anxiety has peaked. The cut-off point for the current arrangement in 2047 is not so far away. There is no clarity about what Hong Kong’s future status will be after this point. China has changed in ways that no one expected. Newly emboldened, it involves itself in Hong Kong’s affairs now simply because it can. The one-party system is muscular and nationalistic; its attitude towards the outside world is increasingly assertive. Beijing considers Hong Kong within its domestic purview. Anything that remotely smacks of interference is quashed.

The UK’s position in all of this is invidious. The country can’t ignore the century and a half of its involvement with the city. Yet beyond the scope of a moral high ground, and Jeremy Hunt's warnings against Chinese "repression", Britain can claim no special political influence. In Beijing’s eyes, any talk of morality amounts to hypocrisy; it will take no lectures from an old colonising power that did nothing to reform the governance of Hong Kong, and is now buried in its own political travails.

The current situation is treacherous. China has indicated the turbulence it may create as it builds influence on the global stage. Perpetual political unrest in Hong Kong threatens the very thing that the city still has as its trump card – a global, rules base, stable commercial centre. The UK, too, is supposed to be forging a new set of post-Brexit relations with partners like China, not bickering with the country about its own politics. The current regime in Beijing talks often of “win-win” outcomes for both Mainland China and Hong Kong. But as things stand in the city, almost a quarter of a century after the handover, matters are altogether more internecine.

Kerry Brown is director of the Lau China Institute at King's College London and the author of “The World According to Xi” (IB Tauris).