"If China imposes its national security law, the British government will change our immigration rules and allow any holder of these passports from Hong Kong to come to the UK for a renewable period of 12 months and be given further immigration rights, including the right to work, which could place them on a route to citizenship", Johnson's article read.
The prime minister noted that the aforementioned 350,000 Hong Kongers would be allowed to stay in the United Kingdom for six months without a visa, adding that another 2.5 million would be eligible to apply for them.
"This would amount to one of the biggest changes in our visa system in British history. If it proves necessary, the British government will take this step and take it willingly", Johnson added.
The minister noted that he expected China to be committed to international agreements and vowed that the United KIngdom would continue to raise this issue on global platforms.
"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", the article read.
The Chinese parliament passed a resolution last week, under which the Standing Committee of China's National People's Congress will be in charge of developing a national security law for Hong Kong that bans secessionist and subversive activity. In response to the legislation, UK Foreign Secretary Dominic Raab said in parliament on Tuesday that China's impending law clearly violated its obligations to London and the world, adding that some 350,000 Hong Kong residents who hold British National Overseas (BNO) passports would be provided with a pathway to UK citizenship in this case.