HONG KONG (Reuters) – Britain will not walk away from the people of Hong Kong if China imposes a national security law that would conflict with its international obligations under a 1984 accord, Prime Minister Boris Johnson said on Wednesday.

Johnson’s remarks followed a warning to China on Tuesday to step back from the brink over the national security legislation for Hong Kong, saying it risked destroying one of the jewels of Asia’s economy while ruining the reputation of China.

“Hong Kong succeeds because its people are free,” Johnson wrote in the Times. “If China proceeds, this would be in direct conflict with its obligations under the joint declaration, a legally binding treaty registered with the United Nations.”

China’s parliament approved last week a decision to create laws for Hong Kong to curb sedition, secession, terrorism and foreign interference.

Mainland security and intelligence agents may, for the first time, be stationed in the city, a former British colony that returned to Chinese rule in 1997.

The plan for the legislation follows months of often violent pro-democracy protests in last year that plunged Hong Kong into its biggest crisis since the handover.

“Many people in Hong Kong fear that their way of life — which China pledged to uphold — is under threat,” Johnson said.

“If China proceeds to justify their fears, then Britain could not in good conscience shrug our shoulders and walk away; instead we will honour our obligations and provide an alternative.”

Johnson repeated Britain’s pledge to give British National Overseas passport-holders in Hong Kong a path to British citizenship, allowing them to settle in the United Kingdom.

There are about 350,000 holders of BNO passports in Hong Kong and another 2.5 million are eligible for them, Johnson said.

China’s decision to impose the national security law on Hong Kong would “curtail its freedoms and dramatically erode its autonomy”, Johnson wrote in a commentary for the South China Morning Post bit.ly/3gGrNC6 newspaper.

“Since the handover in 1997, the key has been the precious concept of ‘one country, two systems’, enshrined in Hong Kong’s Basic Law and underpinned by the Joint Declaration signed by Britain and China,” Johnson wrote.

The Basic law is Hong Kong’s mini constitution while the 1984 declaration set out the arrangements for Hong Kong’s return to China.

Authorities in Beijing and Hong Kong have repeatedly said the security legislation, not yet drafted but expected to be implemented by September, would not affect the city’s high degree of autonomy including its common-law, independent legal system.

‘IRRESPONSIBLE’

China said its decisions on national security in Hong Kong were its own affair and Britain’s connection to the territory stemmed from “aggressive colonisation and unequal treaties”.

“The UK’s irresponsible remarks and accusations … have grossly interfered in China’s internal affairs including Hong Kong affairs,” Chinese foreign ministry spokesman Zhao Lijian said. “We advise the UK side to step back from the brink.”

“The UK said the legislation is authoritarian, but this word is the exact characterization of the UK’s former rule over HK,” the spokesman said.

Johnson’s comments come after U.S. President Donald Trump, responding to Beijing’s plan to impose the security legislation, ordered his administration to begin the process of eliminating special U.S. treatment for Hong Kong to punish China.

A survey of U.S. businesses revealed deep fears for the future of their operations in Hong Kong, with 30% of respondents “moderately” concerned and 53.3% “very concerned” about it.

The survey, on June 1-2 for the American Chamber of Commerce (Amcham), drew responses from 180, or 15%, of its members.

About 60% thought the legislation would harm their business operations, while a third said they were considering moving capital, assets or operations out of the semi-autonomous city, with 38% personally considering moving out.

Contributing to simmering anti-government tension, Hong Kong lawmakers are set to resume debate on a bill that would criminalise disrespect of China’s national anthem, following scuffles in the legislature in recent weeks.

ANNIVERSARY

Separately, Hong Kong activists plan to rally to mark the June 4, 1989, anniversary of Chinese troops opening fire on pro-democracy students in and around Tiananmen Square, even though for the first time, an annual vigil for the anniversary has been cancelled over coronavirus concerns.

Demonstrations are also planned for the June 9 anniversary of last year’s million-strong march against a now-withdrawn bill to allow for the extradition of offenders to mainland China, and protests three days later that police tackled with tear gas and rubber bullets.

The turmoil has raised questions about Hong Kong’s role as a financial hub.

HSBC Holdings (HSBA.L) is among companies that have faced pressure to support the security law, with former Hong Kong leader Leung Chun-ying criticising the bank for not making clear its stance.