They decided to apply early over fears that the Chinese government may launch more retaliatory measures targeting the British scheme.

The new BNO visa scheme - launched at 5pm on Sunday - allows BNO status holders and their immediate family members to live in Britain and apply for settlement after spending five years in the country and offers a pathway to citizenship after a further 12 months.

Some 100 people visited the North Point center yesterday to have their biometrics taken after making an online application.

Among them was a couple, Jason and Samantha, who decided to apply for the visa right after it launched as they were worried that Beijing and the SAR will launch more BNO countermeasures after no longer recognizing the BNO passport as a valid travel document and proof of identity.

"We had planned to emigrate but the recent social events made us decide to do this earlier," said Samantha.

Another applicant, Cheung, said she is rushing as she wants her two children to adapt to the new environment earlier.

"The political environment [in Hong Kong] is unhealthy, so we want to start a new life and move there as soon as possible," she said.

Meanwhile, lawmaker Regina Ip Lau Suk-yee said Beijing's refusal to recognize BNO passports is only a symbolic move with little actual consequences, as Hongkongers are still able to enter or leave the city using SAR passports and Hong Kong ID cards.

Hong Kong authorities would only consider taking further action if a large number of Hongkongers emigrate to the UK or the UK government shows hostility against China and the SAR again, she said.

But Ip said those worried about arrests under the security law have already left the city.

She also warned immigrants who are not familiar with the local culture of the UK may face discrimination.

Authorities in Beijing should consider enforcing the Chinese nationality law and revoke the nationality of Hongkongers who immigrate, Ip said.