The U.K. prime minister told MPs on Wednesday the stringent new laws represented a “clear and serious breach” of China’s obligations under the Sino-British Declaration, the treaty that has underpinned Hong Kong’s status since the U.K. handed over sovereignty in 1997.

London had previously threatened to offer Hong Kong residents with British National Overseas status — estimated by the U.K. government to number 2.9 million — a “path to citizenship” if Beijing pressed ahead with its plan to impose the measures on Hong Kong.

Johnson said in the House of Commons the U.K. would follow through on its pledge.