The US and British governments called for the release of pro-democracy tycoon Jimmy Lai, who stood trial Monday in Hong Kong for national security charges that could send him to jail for life.

Lai, 76, stands accused of "collusion" with foreign forces under a sweeping national security law that Beijing imposed on the finance hub in 2020.

He is the founder of the now-shuttered Chinese-language tabloid Apple Daily, which often criticised Beijing and supported the huge protest movement that roiled Hong Kong in 2019.

The trial -- scheduled to be heard in open court over the next 80 working days -- will be closely watched as a barometer for the city's political freedoms and judicial independence.

A rags-to-riches millionaire who made his fortune selling clothes before expanding into media, Lai will be tried without a jury and has been denied his choice of lawyer.

On Monday, Lai -- who has not been publicly seen since 2021 -- appeared in court in a suit, and smiled and waved at the gallery where his family sat.

Observers from Hong Kong's foreign consulates -- including the United States, Britain, Australia and Canada -- were present for the trial.

His case has drawn widespread condemnation from the international community, but Beijing has dismissed the criticism as smears and interference.

British Foreign Secretary David Cameron said in a statement ahead of the proceedings that he was "particularly concerned at the politically-motivated prosecution" of Lai.

"As a prominent and outspoken journalist and publisher, Jimmy Lai has been targeted in a clear attempt to stop the peaceful exercise of his rights to freedom of expression and association.

"I call on the Hong Kong authorities to end their prosecution and release Jimmy Lai," he said.

US State Department spokesman Matthew Miller also called for Lai's release, saying that "actions that stifle press freedom and restrict the free flow of information... have undermined Hong Kong's democratic institutions and harmed Hong Kong's reputation as an international business and financial hub".

A heavy security presence was deployed outside the court Monday, with an armoured vehicle and police donning tactical gear.

Police stopped Alexandra Wong, an activist better known as "Grandma Wong", from approaching the court's entrance.

"Support Apple Daily, support Jimmy Lai!" she shouted while waving the UK flag, before police escorted her to the other side of the road.

"The trial is very unfair, very unreasonable," she told reporters.

Dozens of activists have been charged under the 2020 national security law, but Lai is the first to contest a foreign "collusion" charge.

Imprisoned for more than 1,100 days, Lai has already been convicted in five other cases, including for organising and participating in marches during the 2019 democracy protests.

- Litmus test -

 

To attend the trial, members of the public queued overnight in frigid temperatures outside Hong Kong's West Kowloon Law Courts Building.

"I don't want him to appear in court and find no one attending the hearing," said Jolly Chung, a part-time caterer who arrived around 10 pm Sunday to ensure herself a spot in court, adding that she saw Lai's case as a litmus test for Hong Kong's freedoms.

"Press freedom does not only affect journalists. An ordinary reader could also write and publish," she told AFP.

Lai's Apple Daily was forced to close in 2021 after authorities used the security law to raid it twice and freeze assets worth HK$18 million (US$2.3 million).

Critics of the national security law say it has curtailed civil liberties, effectively silenced dissent and eroded the judicial independence that has long attracted foreign businesses to the financial hub.