Calls to denounce “die hard” Taiwanese secessionists, a tipline to report them and punishments that could include the death penalty for “ringleaders” – Beijing’s familiar rhetoric against Taiwan is turning dangerously real.

The democratically-governed island has grown used to China’s claims. Even the planes and ships that test its defences have become a routine provocation. But the recent moves to criminalise support for it are unnerving Taiwanese who live and work in China, and those back home.

“I am currently planning to speed up my departure,” a Taiwanese businesswoman based in China said – this was soon after the Supreme Court ushered in changes allowing life imprisonment and even the death penalty for those guilty of advocating for Taiwanese independence.

“I don’t think that is making a mountain out of a molehill. The line is now very unclear,” says Prof Yu Jie, a legal scholar at Taiwan’s Academia Sinica.

China’s Taiwan Affairs Office was quick to assure the 23 million Taiwanese that this is not targeted at them, but at an “extremely small number of hard-line independence activists”. The “vast majority of Taiwanese compatriots have nothing to fear,” the office said.

But wary Taiwanese say they don’t want to test that claim. The BBC has spoken to several Taiwanese who live and work in China who said they were either planning to leave soon or had already left. Few were willing to be interviewed on record; none wanted to be named.

“Any statement you make now could be misinterpreted and you could be reported. Even before this new law China was already encouraging people to report on others,” the businesswoman said.

That was made official last week when Chinese authorities launched a website identifying Taiwanese public figures deemed “die hard” separatists. The site included an email address where people could send “clues and crimes” about those who had been named, or anyone else they suspected.

Scholars believe Beijing hopes to emulate the success of Hong Kong’s national security laws, which it said were necessary for stability – but they have crushed the city’s pro-democracy movement as former lawmakers, activists and ordinary citizens critical of the government have been jailed under them.

By making pro-Taiwanese sentiments a matter of national security, Beijing hopes to “cut off the movement’s ties with outside world and to divide society in Taiwan between those who support Taiwan independence and those who do not”, says Prof Chen, a legal scholar at Taiwan’s Academia Sinica.

She says the guidance from the Supreme Court will almost certainly result in prosecutions of some Taiwanese living in China.

“This opinion has been sent to all levels of law enforcement nationwide. So this is a way of saying to them – we want to see more cases like this being prosecuted, so go and find one.”

“We must be even more cautious,” said a Taiwanese man based in Macao. He said he had always been prepared for threats, but the new legal guidance had made his friends “express concern” about his future in the Chinese city.

“In recent years, patriotic education has become prevalent in Macau, with more assertive statements on Taiwan creating a more tense atmosphere compared to pre-pandemic times,” he added.

Taiwan, which has powerful allies in the US, the EU and Japan, rejects Beijing’s plans for “reunification” – but fears have been growing that China’s Xi Jinping has sped up the timeline to take the island, an avowed goal of the Chinese Communist Party.

For more than 30 years Taiwanese companies – iPhone-maker Foxconn, advanced chips giant TSMC and electronics behemoth Acer – have played a key role in China’s growth. The prosperity also brought Taiwanese from across the strait who were in search of jobs and brighter prospects.

“I absolutely loved Shanghai when I first moved there. It felt so much bigger, more exciting, more cosmopolitan than Taipei,” says Zoe Chu*. She spent more than a decade in Shanghai managing foreign musicians who were in high demand from clubs and venues in cities across China.

This was the mid-2000s when China was booming, drawing money and people from across the globe. Shanghai was at the heart of it – bigger, shinier and trendier than any other Chinese city.

“My Shanghainese friends were dismissive of Beijing. They called it the big northern village,” Ms Chu recalls. “Shanghai was the place to be. It had the best restaurants, the best nightclubs, the coolest people. I felt like such a country bumpkin, but I learned fast.”

By the end of that decade – in 2009 – more than 400,000 Taiwanese lived in China. By 2022, that number had plummeted to 177,000, according to official figures from Taiwan.

“China had changed,” says Ms Chu, who left Shanghai in 2019. She now works for a medical company in Taipei and has no plans to return.

“I am Taiwanese,” she explains. “It’s no longer safe for us there.”

The Taiwanese exodus has been driven by the same things that have pushed huge numbers of foreigners to leave China – a sluggish economy, growing hostility between Beijing and Washington and, most of all, the sudden and sweeping lockdowns during the Covid pandemic.

But Taiwanese in China have also been worried because the government doesn’t see them as “foreigners”, which makes them especially vulnerable to state repression.

Senior Taiwanese officials have told the BBC that 15 Taiwanese nationals are currently being held in China for various alleged crimes, “including violations of the anti-secession law”.

In 2019, China jailed a Taiwanese businessman for espionage after he was caught taking photos of police officers in Shenzen – a charge he denied. He was only released last year. In April 2023, China confirmed that it had arrested a Taiwan-based publisher for “endangering national security”. He still remains in custody.

Amy Hsu*, who once lived and worked in China, says she is now scared to even visit because of her job. After returning to Taiwan, she began volunteering at an NGO which helped people who had fled Hong Kong to settle in Taiwan.

“It is definitely more dangerous for me now,” she says. “In 2018, they began using surveillance cameras to fine people for jaywalking and the system could identify your face and send the fine directly to your address.”

She says the extent of surveillance disturbed her – and she worries it can be used to go after even visitors, especially those on a list of potential offenders.

“Oh I am definitely on the list. I am a hardline pro-independence [guy] with lots of ideas,” chuckles Robert Tsao, a 77-year-old tech billionaire, who founded one of Taiwan’s largest chip-makers, United Micro-electronics Corporation (UMC).

Mr Tsao was born in Beijing, but today he supports Taiwan independence and avoids not just China, but also Hong Kong, Macau, Thailand and even Singapore.

Mr Tsao was not always hostile to China. He was one of the first Taiwanese investors to set up advanced chip-making factories in China. But he says the crackdown in Hong Kong changed his mind: “It was so free and vibrant and now it’s gone. And they want to do the same to us here.”

“This new ruling is actually helping people like me,” he says. He believes it will backfire, increasing the resolve of Taiwanese people to resist China.

“They say the new law will only affect a few hard-line independence supporters like me, but so many Taiwanese people either support independence or the status quo [keep things as they are], which is the same thing, so we have all become criminals.”

* Names changed on request of contributors