Britain on Friday hailed a new visa offering Hong Kong citizens a route to citizenship after China's crackdown but Beijing said it would no longer recognise special British passports offered to residents of the former colony.
Britain and China have been bickering for months about what London and Washington say is an attempt to silence dissent in Hong Kong, though Beijing says the West's views are clouded by misinformation and an imperial hangover.
Britain says it is fulfilling a historic and moral commitment to the people of Hong Kong after China imposed a tough new security law on the city that Britain says breaches the terms of agreements to hand the colony back in 1997.
"I am immensely proud that we have brought in this new route for Hong Kong BN(O)s to live, work and make their home in our country," Prime Minister Boris Johnson said, referring to a special British National Overseas (BNO) passport.
"In doing so we have honoured our profound ties of history and friendship with the people of Hong Kong, and we have stood up for freedom and autonomy – values both the UK and Hong Kong hold dear."
But China hit back by saying it would not recognise the BNO passport as a valid travel document from Jan. 31.
"Britain is trying to turn large numbers of Hong Kong people into second-class British citizens. This has completely changed the original nature of BNO," Chinese foreign ministry spokesman Zhao Lijian told a regular briefing.
Beijing's decision not to recognise the travel document is largely symbolic as Hong Kong residents would not normally use their BNO passports to travel to the mainland.
Beijing's imposition of a national security law in the former British colony in June last year prompted Britain to offer refuge to almost 3 million Hong Kong residents eligible for the BNO passport from Jan. 31.
The scheme, first announced last year, opens on Sunday and allows those with "British National (Overseas)" status to live, study and work in Britain for five years and eventually apply for citizenship.
BN(O) is a special status created under British law in 1987 that specifically relates to Hong Kong.
The new 250 pound ($340) visa could attract more than 300,000 people and their dependents to Britain and generate up to 2.9 billion pounds net benefit to the British economy over the next five years, according to government forecasts.
From around midday on Sunday, eligible applicants can apply online and book an appointment to register their fingerprints at a visa application centre. From Feb. 23 some will be able to make the application via a smartphone app.
It is still highly uncertain how many people will actually take up the offer. Government estimates show that 2.9 million people and a further 2.3 million dependents will be eligible to come to Britain.