Not a day goes by without Hong Kong democracy activist Joshua Wong wondering how long it will be before the police's new national security unit comes for him.

The 23-year-old is the city's most high-profile political dissident, and has twice been jailed for leading anti-government protests in the city.

But since Beijing imposed a draconian new security law in July, the stakes have risen significantly.

Wong says he is not clear whether those now regularly following him are Hong Kong police or mainland agents
Wong says he is not clear whether those now regularly following him are Hong Kong police or mainland agents AFP / ISAAC LAWRENCE

"Every day when I sleep, I can't imagine when will the police storm into my home," Wong told AFP.

"The question for every activist is how much private life is still left?

"How much time we can spend with our friends before the day Beijing arrests us with the national security law?"

Wong knew the law would dramatically alter the semi-autonomous city's freedoms, which China pledged to protect until 2047 under the handover deal with Britain.

Joshua Wong is Hong Kong's most high-profile political dissident, and has twice been jailed for leading anti-government protests in the city
Joshua Wong is Hong Kong's most high-profile political dissident, and has twice been jailed for leading anti-government protests in the city AFP / ISAAC LAWRENCE

And it wasn't long before he saw firsthand how his own daily life had changed.

In mid-July he was on his way to submit his candidacy to stand in local elections -- an application rejected because of his political views -- when he noticed a convoy of at least six vehicles following him.

"It's like one of those Hollywood movies," Wong recalled. "The drivers even held the walkie-talkies to co-ordinate."

Beijing's security law was designed to stamp out the huge and often violent pro-democracy protests that convulsed Hong Kong last year
Beijing's security law was designed to stamp out the huge and often violent pro-democracy protests that convulsed Hong Kong last year AFP / May JAMES

One of the many provisions of the new security law was to allow mainland security agents to operate openly in Hong Kong for the first time, and they moved into a requisitioned luxury hotel days after the legislation passed in June.

Wong says he is not clear whether those now regularly following him are Hong Kong police or mainland agents.

He has mostly stopped taking public transport -- instead asking friends to be his drivers or bodyguards -- and has upgraded security on his digital devices.

Wong describes himself as a big fan of the Japanese robot franchise Gundam, a self-confessed bad driver and an avid watcher of US political drama "House of Cards"
Wong describes himself as a big fan of the Japanese robot franchise Gundam, a self-confessed bad driver and an avid watcher of US political drama "House of Cards" AFP / ISAAC LAWRENCE

"Freedom, privacy and safety are no longer taken for granted in Hong Kong since the law was implemented," he remarked.

Beijing's security law was designed to stamp out the huge and often violent pro-democracy protests that convulsed Hong Kong last year.

It targets acts deemed to be secession, subversion, terrorism and foreign collusion and Beijing has described it as a "sword" hanging over the heads of its opponents as it pushes to return stability.

Critics say it has blanketed the city in fear, and UN rights experts warned its broad wording posed a serious risk to Hong Kong's freedoms.

Wong described a delicate balancing act between his public political life, and his private persona -- but believes his prominence does provide some protection
Wong described a delicate balancing act between his public political life, and his private persona -- but believes his prominence does provide some protection AFP / Anthony WALLACE

Wong knows he is a prime target.

Having spent most of his teenage years leading protests he has been dubbed a leading "anti-China rabble-rouser" by Beijing.

The security law has already swept up two of his closest comrades.

Fellow former student leader Nathan Law has fled to Britain and is now wanted for national security crimes according to Chinese state media.

Agnes Chow -- who has led protests alongside Wong since they were just 15 -- is one of 22 people arrested under the new law so far. She has been released on bail.

Wong described a delicate balancing act between his public political life, and his private persona -- but believes his prominence does provide some protection.

"Being a high-profile activist, sometimes when the regime needs to target you, they also have a bit more hesitation," Wong said.

He describes himself as a big fan of the Japanese robot franchise Gundam, a self-confessed bad driver and an avid watcher of US political drama "House of Cards".

Wong is also a fan of the popular online game "Animal Crossing", but even that has become entangled with politics.

When Hong Kong fans of the game festooned their virtual islands with pro-democracy imagery, the product was promptly pulled from mainland Chinese app stores.

Many users blamed Wong, a sign of the vitriol he has long endured in the increasingly polarised city.

Last month he and a friend went dog walking, and were tailed by an SUV, whose occupants got out to film and berate him, calling him a "traitor".

"They even scolded the dog," he recalled.

But Wong says he has no plans to scale back his activism.

"It seems to be a zero sum game," he said.

"If they choose not to arrest me, I may still be in Hong Kong, but if they choose to arrest me, I may be extradited to China immediately.

"And that's the end."