International condemnation was swift, with Western countries and rights groups slamming the sentencing as evidence of the erosion of political freedoms in the city since Beijing imposed a security law in 2020.

Tai's sentence was the longest yet handed out under the law, which was brought in to quash dissent after massive, sometimes violent pro-democracy protests in 2019.

His 44 co-defendants were sentenced to shorter terms beginning from four years and two months.

All were charged with subversion after holding an informal poll in 2020 as part of a strategy to win a pro-democracy electoral majority.

The group is made up of some of the most prominent figures of Hong Kong's once-diverse political opposition.

Among them, former student leader Joshua Wong shouted "I love Hong Kong, bye bye!" to the packed courtroom as he was led away after sentencing.

Wong gained international prominence in 2014 as a driving force behind protests known as the Umbrella Movement, which landed him on the cover of Time magazine when he was just a teenager.

- 'The wicked shall perish' -

More than 200 people had queued in drizzle outside the court since dawn for a public seat.

Inside, the 45 defendants were crammed into the dock, occasionally waving to the public.

Many have already spent more than 1,300 days in jail.

Outside after the sentencing, the mother of defendant Hendrick Lui silently held up a placard reading: "The righteous shall live, the wicked shall perish."

She was taken away in a police van within seconds, according to video footage from Hong Kong media.

The second-longest sentence of seven years and nine months was handed to young activist Owen Chow.

Pro-democracy politicians Au Nok-hin, Andrew Chiu and Ben Chung were singled out as organisers, but received lesser sentences after testifying against Tai.

"Long Hair" Leung Kwok-hung, the 68-year-old co-founder of the city's last standing opposition party, received a term of six years and nine months.

His wife and party leader Chan Po-ying told AFP that it was "within our expectations".

"It is what it is -- no matter (whether) I laugh or I cry, so I choose to laugh a bit," she said.

Also included in the group are former lawmakers like Claudia Mo and Eddie Chu, and former journalist Gwyneth Ho.

- 'Refused to be tamed' -

Former district councillor Leticia Wong told AFP that she thought the sentences were "encouraging people to plead guilty and testify against their peers".

"For those who refused to be tamed, punishment is obviously heavier," Wong said.

Western countries and international rights groups condemned the trial.

Australia's government said it was "gravely concerned" after dual citizen Gordon Ng received a sentence of seven years and three months, and said it would continue to advocate for his "best interests".

The United States and Britain also condemned the sentences of the 45 activists.

China responded that such Western criticism "seriously desecrates and tramples on the spirit of the rule of law", and warned against interference.

International NGO Human Rights Watch said the sentences show "how fast Hong Kong's civil liberties and judicial independence have nosedived".

Another closely watched national security trial will see a key development on Wednesday when jailed pro-democracy media tycoon Jimmy Lai testifies in his collusion trial.

China and Hong Kong have repeatedly pushed back against criticisms, saying the security law restored order following the 2019 protests.

Hong Kong's security minister Chris Tang said Tuesday's sentences "reflected the severity of the crime", but added the government would decide whether to appeal individual sentences.

- 'Constitutional crisis' -

Forty-seven people were initially charged after they were arrested in January 2021.

Thirty-one pleaded guilty, and 16 stood a 118-day trial last year, with 14 convicted and two acquitted in May.

The aim of the July 2020 primary was to pick a cross-party shortlist of pro-democracy candidates to increase their electoral prospects.

If a majority was achieved, the plan was to force the government to meet the 2019 protesters' demands -- including universal suffrage -- by threatening to indiscriminately veto the budget.

Three senior judges handpicked by the government to try security cases said that would have caused a "constitutional crisis".

The subversion charge could have carried a sentence of up to life in prison.