Hong Kong leader Carrie Lam said  that elections for the city legislature will be postponed from  6 September due to a spike in coronavirus cases,dealing a major blow to the city's pro-democracy opposition.

The opposition was hoping to win a historic majority in the Legislative Council, where only half the seats are directly elected and the other half stacked with pro-Beijing figures.

Ms Lam's move comes after 12 pro-democracy candidates were disqualified from running in the poll, on reasons including perceived subversive intentions, opposition to a new national security law and campaigning to win a legislation-blocking majority.

The poll would have been Hong Kong's first official vote after China imposed a sweeping new security law that critics say aims to quash dissenting voices in China's freest city and bring the semi-autonomous territory on a more authoritarian path.

Hong Kong's democracy supporters were dealt a huge blow as authorities postponed the elections, capping a devastating month of political disqualifications, arrests for social media posts and activists fleeing overseas.

The city's democracy camp has come under sustained attack since Beijing imposed a sweeping national security law on the city last month - a move China's leaders described as a "sword" hanging over the head of its critics.

The ensuing weeks have radically transformed a city used to speaking its mind and supposedly guaranteed certain freedoms and autonomy in a "One Country, Two Systems" deal agreed ahead of its 1997 handover from Britain.

Today chief executive Carrie Lam, a pro-China appointee, announced that the would need to be delayed.

She described the announcement as the "most difficult decision" she has made since the pandemic began and that Beijing supported the move. 

The decision will infuriate democracy supporters who had warned against any moves to delay the polls, accusing authorities of using the pandemic to avoid a drubbing at the ballot box.

It also came a day after a dozen prominent democracy activists were barred from standing for election because their political views were deemed to be unacceptable.

Hong Kong is not a democracy - its leader is chosen by pro-Beijing committees. 

But half of its legislature's 70 seats are directly elected, offering the city's 7.5 million residents a rare chance to have their voices heard at the ballot box.

Planning to capitalise on last year's huge and often violent anti-Beijing protests, democracy activists had been hoping to win their first-ever majority in September.

But officials have begun scrubbing ballot lists of candidates. 

Examples given by authorities of unacceptable political views have included criticising a new security law imposed by Beijing, campaigning to win a legislation-blocking majority and refusing to recognise China's sovereignty.

Earlier in the day a coalition of democracy parties warned any bid to delay the elections would be herald "the complete collapse of our constitutional system.

Around half of Hong Kong's 3,100 Covid-19 cases have been detected in the past month and authorities fear hospitals are on the verge of being overwhelmed.

According to the International Institute for Democracy and Electoral Assistance, at least 68 elections worldwide have been postponed because of the virus, while 49 went ahead.