The daughter of Jimmy Lai, the pro-democracy tycoon jailed in Hong Kong, has expressed concerns about her father's deteriorating health in prison, saying that his fingernails sometimes fall off and his teeth are rotting.

Lai, 78, has been detained since December 2020 and faces life in prison. Earlier this month he was convicted of colluding with foreign forces under the city's controversial national security law (NSL).

Hong Kong and Chinese authorities have denied that Lai has been mistreated in prison, stating he is in good health.

The BBC has seen a letter written by Lai's family urging UK Prime Minister Keir Starmer to call for Lai's release when he meets Chinese President Xi Jinping next month.

His daughter Claire Lai, who is in exile in London, told the BBC that she fears she may never see him again. She stated, Of course I worry that my father is going to be a martyr, and I don't want him to be a martyr. But I would not be here today, I would not be speaking out if I didn't think this was his best chance of reuniting with our family.

Describing her father as an extremely robust and strong man prior to his imprisonment, Claire noted that he has experienced significant weight loss and now deals with chronic health issues. She shared details such as:
- His fingernails turning purplish grey and sometimes falling off.
- Teeth that are rotting.
- Back and waist pains, leading to difficulties standing and getting out of bed.

On multiple occasions, the family has raised concerns about Lai's declining health, with his son earlier mentioning that his father's body is breaking down.

A spokesperson for the Chinese Foreign Ministry in Hong Kong has previously stated that Lai's lawful rights and interests have been fully protected, denying claims of mistreatment.

Lai, who holds UK citizenship, is the most notable figure prosecuted under the NSL that was enacted in 2020 amid significant pro-democracy protests in Hong Kong. Critics argue that the law effectively criminalizes dissent, whereas Beijing contends it is crucial for maintaining stability.

Following his recent conviction, the UK government condemned the ruling as politically motivated persecution, reaffirming calls for the law's repeal and an end to the prosecution of individuals charged under it.

Starmer's upcoming trip to China in late January 2026 marks the first visit by a UK Prime Minister since 2018.