Looking drained and sporting a prison buzz cut, political activist Joshua Wong is trying to put a brave face on the tribulations facing Hong Kong's democracy movement.

"Hong Kong has entered an era where those who fight for democracy and free elections will be put in prison," the 21-year-old tells the Financial Times, several days after he was released on bail 69 days into a six-month sentence for his role in kick-starting the 2014 Occupy protests. "But I still see hope because even people who are not ready to face life in prison are ready to show their support."

As he prepares for his possible return to prison, Wong admits that Beijing's intensifying crackdown has left activists with fewer avenues for resistance and higher penalties for defying the authorities.

"We don't have concrete plans on how to get universal suffrage from Beijing," he says, as he sips on a Coke and expresses relief at his chance to "taste freedom" now that he is out of jail, where he could only drink water.

Beijing — and the semi-autonomous Hong Kong government — was taken aback by the scale of the Occupy protests and a subsequent movement led by young Hong Kongers such as Wong that called for self-determination or even independence for the city.

Over the past two years the authorities have hit back with a widening crackdown that has seen booksellers kidnapped and taken to the mainland, outspoken lawmakers ousted from the Legislative Council and, in August, more than a dozen young protesters including Wong jailed for unlawful assembly.

The campaign has put the democracy movement on the back foot and stoked broader fears about the erosion of the autonomy and civic freedoms promised to the former British colony for 50 years when it was handed over to China in 1997.

President Xi Jinping has warned that he will not allow Hong Kong to be used to subvert the authority of the government, with other top officials saying the city's autonomy is at risk if this continues.

Lau Siu-kai, the vice-president of the Chinese government's think-tank on Hong Kong and Macau affairs, says the "rules of the game" are changing for Hong Kong, as Beijing reasserts its authority.

"Beijing will assume a bigger role in securing sovereignty, national security and its development interests instead of relying on the Hong Kong government and people," he says. "In this situation, a serious fight between Beijing and some in Hong Kong is inevitable."

Mr Lau says Beijing will step up its propaganda efforts in Hong Kong, boost the role of "patriots" in the city and use tools of direct influence in Hong Kong's mini-constitution, including the power to "interpret" local laws and force the local government to implement its directives.

The Hong Kong government, led by chief executive Carrie Lam, has dismissed claims that the city is entering an "authoritarian" era and insists it will set aside controversial political problems to focus on livelihood issues such as the high cost of housing.

But, speaking privately, several senior Hong Kong officials admit that if the city cannot curb calls for independence and self-determination, which are anathema to Beijing, the Chinese government will further intensify its interventions.

Kevin Carrico, a lecturer in Chinese studies at Australia's Macquarie University, says activists are "tired and not sure what to do to reverse these trends".

"As there's this gradual tightening in one field after another, we'll eventually see a situation where there's no way out but moving to Taiwan or somewhere else," he says.

Joshua Wong, a Hong Kong student activist, is arrested after a protest in June 2017 © EPA

In Wong's case, he will be sent back to jail next week if he fails to win leave to appeal his sentence for illegal assembly, after he and a group of protesters stormed a square in front of a government building in 2014. Upcoming court hearings related to Occupy could lead to more pro-democracy politicians being jailed and further prison sentences for Wong and some of his allies.

For now, he is enjoying his freedom, playing computer games, getting reacquainted with his smartphone and using chopsticks, knives and forks — which were banned in prison for fear of self-harm.

But as he struggles to divide his time out of prison between his political activities and his family and friends, Wong calls for his fellow Hong Kongers to think of the lesser-known activists facing much longer jail sentences.

"It's ironic that I'm the one serving the least time but I get the most coverage," he says. "That's why I felt uncomfortable when I got bail. Don't just focus on the one identified as a hero."

Additional reporting by Nicolle Liu