Security has been tightened in Hong Kong as lawmakers resume a debate over a bill that would make disrespecting China's national anthem a criminal offence.
The new law is seen as China's plans to impose national security laws on Hong Kong, with the UK stepping up criticism of the move.
Prime Minister Boris Johnson reiterated that Britain will not walk away from the people of Hong Kong and stressed that the national security law contradicts the 1984 accord.
He also repeated Britain's pledge to give British National Overseas passport-holders in Hong Kong a path to citizenship.
Meanwhile, Hong Kong leader Carrie Lam accused foreign governments on Tuesday of "double standards" and refused to back down.
It comes as the annual vigil to commemorate the bloody 1989 Tiananmen Square crackdown on pro-democracy demonstrators in Beijing has been cancelled.


Tanzania's Hassan declared landslide winner in election marred by violence
Vietnam's ancient town Hoi An works to restore tourism after devastating floods
Indian temple stampede kills nine, injures several
Turkey to host Gaza meeting amid ceasefire concerns
Tanzania opposition says hundreds killed in vote protests
Turkey sentences 11 people to life in prison over ski resort hotel fire
China sends its youngest astronaut to 'Heavenly Palace' space station
Israel launches more strikes on Gaza overnight, testing fragile truce
