HONG KONG (NYTIMES) - A former employee of the British Consulate in Hong Kong who said he was tortured by the authorities in mainland China last year has been given asylum in Britain.

The disappearance last year of the consulate worker, Mr Simon Cheng, during the height of pro-democracy demonstrations in Hong Kong highlighted the issues that had set off months of protest.

Hong Kongers took to the streets in part over fears that they could be subject to the opaque Chinese legal system as mainland officials expand their reach over people in semi-autonomous Hong Kong, a former British colony.

"I am grateful for the determination and courage shown by the UK government to rescue British nationals," Mr Cheng wrote on Facebook above a photo of the letter granting him asylum. "I also hope my case can be a precedent for other Hong Kongers to seek for protection."

The British Foreign Office could not immediately be reached for comment.

The asylum for Cheng came amid scattered unrest in Hong Kong on Wednesday (July 1) after China imposed a national security law on Hong Kong that seeks to stamp out displays of dissent against the Beijing government.

The move has prompted recriminations from other nations against China and spurred fears that it spells the end of the "one country, two systems" framework that had distinguished the territory.

The Hong Kong police, which made several arrests under the law during protests on Wednesday, said a 24-year-old man suspected of stabbing a police officer was arrested early on Thursday at the city's airport.

Local news outlets said he had been preparing to depart for London.

The British government on Wednesday confirmed plans to open a pathway for as many as three million people from Hong Kong to obtain British citizenship. The country's Foreign Secretary Dominic Raab said the decision was in response to the "grave and deeply disturbing" new security law.

Mr Raab called the law a breach of the Joint Declaration, the 1984 treaty under which Britain agreed to return Hong Kong in 1997. He said the law violated the city's autonomy, threatened civil rights and undermined judicial independence.

US Secretary of State Mike Pompeo called the law "outrageous and an affront to all nations" because under one of its articles, even non-residents of Hong Kong could conceivably be punished for running afoul of Chinese law.

When the Chinese government first announced plans to impose the national security law on Hong Kong, Mr Cheng warned that protesters in the city could soon face the same sort of arbitrary detention and abuse that he did.

"After Beijing promulgates the National Security Law in Hong Kong, my enforced confession tape on 'treason' would be the 'evidence', and our pro-democracy activists could be also in danger," he wrote on Facebook.

Last year, Mr Cheng, 29, travelled from Hong Kong to the mainland city of Shenzhen for a business conference and apparently came to the attention of the Chinese authorities.

He was stopped by the police on his return to Hong Kong in the city's high-speed rail station, part of which is under mainland jurisdiction.

He was held for 15 days, during which, he said, he was hooded, hung for hours in a spreadeagled position and beaten to force him to stay awake.

Under such abuse, Mr Cheng said, he gave the authorities the password to his iPhone, information about British Consulate operations and the names of some Hong Kong protesters.

Mr Cheng also gave a videotaped admission to soliciting prostitution, which was later released by the Chinese police.

The police have often publicised confession videos in high-profile cases, which legal experts say are meant to display the state's authority over individuals.

After his release, Mr Cheng denied the allegations against him, insisting his confession had been coerced.

The case strained diplomatic relations between China and Britain, and Beijing's new national security law threatens to damage those ties further.

Mr Raab said on Wednesday that Britain would grant the roughly 350,000 holders of British overseas passports and an additional 2.5 million who are eligible the right to stay in the country for five years and then transition to applying for citizenship.

The British national overseas passport was created for Hong Kong residents but did not give them citizenship rights.

Mr Cheng said that his decision to leave Hong Kong had been a result of political persecution, and that he hoped to return some day when that was no longer a risk.

"Leaving means not an end but a beginning," he added. "We will continue the fight against the expanding totalitarianism, and be back to our home town with true democracy and freedom."