British Prime Minister Boris Johnson is ready to open the door to nearly three million Hong Kong citizens if China imposes a new security law that critics say would rob the territory of its autonomy.

The Prime Minister, writing in The Times, has offered to make what he said would be one of the “biggest changes” in the history of the British visa system to allow 2.85 million Hong Kong citizens the chance of fully-fledged citizenship.

China’s ceremonial legislature, the National People’s Congress, endorsed a security law for Hong Kong earlier this week that has strained relations with Britain and the US.

Protesters marched on the streets in Hong Kong, despite coronavirus social distancing restrictions.

Mr Johnson said the national security law would breach the treaty between China and Britain and would “dramatically erode” Hong Kong’s autonomy.

If China went ahead with its changes for the island, the PM said he would effectively upgrade the status of British National (Overseas) passports, which 350,000 people in Hong Kong hold and 2.5 million are eligible to apply for, to grant immigration rights beyond the current six-month limit.

“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” he said.

“This would amount to one of the biggest changes in our visa system in British history.”

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Mr Johnson added in the article, which was also published in the South China Morning Post “many people in Hong Kong fear their way of life, which China pledged to uphold, is under threat.

“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.”

-with agencies