The case has grown into a wedge between Beijing and many Western nations, with US President Donald Trump reportedly calling for Lai's release during a meeting with Chinese leader Xi Jinping in October.

The Apple Daily founder has pleaded not guilty to two counts of "conspiracy to foreign collusion" under the security law, which carry a maximum penalty of life in prison, as well as one count of "conspiracy to publish seditious publications".

Lai turned 78 last week and once described himself as a "born rebel". He loudly defied the Chinese Communist Party for years, while amassing millions from his clothing and media empires.

He became a prime target after Beijing imposed the sweeping national security law on Hong Kong in 2020, a year after huge and sometimes violent pro-democracy protests in the finance hub.

High Court judges Esther Toh, Alex Lee and Susana D'Almada Remedios will begin delivering their verdicts at 10 am (0200 GMT).

If found guilty, Lai will likely be sentenced at a later date and can appeal the outcome.

A Chinese foreign ministry spokesman said on Friday that Beijing "firmly supports" Hong Kong in "safeguarding national security in accordance with the law and punishing criminal acts that endanger national security".

Lai is a British citizen, and British Prime Minister Keir Starmer has been under pressure from human rights and press freedom groups to secure his release.

- Health concerns -

Lai has been in jail since December 31, 2020, and the state of his health is bitterly contested by his family and the Hong Kong government.

He most recently appeared in court in August, when he was prescribed medication and fitted with a heart rate monitor after lawyers said he had experienced heart palpitations.

Lai gave spirited courtroom testimony and was quick to respond to, and even bicker with, prosecutors and judges.

His daughter Claire told AFP last week that Lai, a diabetic, had "lost a very significant amount of weight" and showed decay in his nails and teeth.

The Hong Kong government said on Friday that Lai has received "adequate and comprehensive" medical services and that "no complaints" had been raised.

Authorities also confirmed that Lai had been held in solitary confinement, but said that "has all along been made at his own request".

- Sprawling trial -

Prosecutors accused Lai during the trial of being the mastermind in a conspiracy involving Apple Daily's senior management, citing 161 items the outlet published.

Those items, which included op-eds with Lai's byline and online talk shows he hosted, were deemed seditious under a colonial-era law because they "excited disaffection" against the government.

Prosecutors said some of the items also breached the later national security law because they asked foreign countries to impose "sanctions or blockade" or take "hostile activities" against Hong Kong or China.

Lai was grilled for days over his political connections in the United States, Britain and Taiwan, including a 2019 meeting with then-US vice president Mike Pence.

Prosecutors separately accused Lai of being the mastermind and financial backer of the protest group "Stand with Hong Kong, Fight for Freedom", which allegedly lobbied for sanctions against China.

Lai countered that he had never tried to influence other countries' foreign policies on Hong Kong and China through his overseas contacts.

He also distanced himself from violence and separatism, saying that Apple Daily represented Hongkongers' core values such as "rule of law, freedom, pursuit of democracy, freedom of speech, freedom of religion, freedom of assembly".

Apple Daily was forced to close in 2021 after police raids and the arrests of its senior editors.

Six of the newspaper's top executives were charged as co-defendants and have already pleaded guilty.