Three men were sentenced to prison for up to 18 years by the High Court over the 2020 bomb plots, as they were found guilty of conspiracy to cause an explosion of a nature likely to endanger life and cause serious injury to property under an alternative charge.

​The first defendant, Ho Cheuk-wai, was sentenced to 18 years' imprisonment on Monday, while the other two, Lee Ka-pan and Cheung Ka-chun, were sentenced to 16 years and eight months.

Ho received an additional six days in prison for violating probation in another conviction of criminal damage in 2019.

​Judge Johnny Chan Jong-Herng stated that Ho was the mastermind with no remorse shown in his psychological report and had no grounds for a reduced sentence, while Lee and Cheung -- who were first-time offenders -- were each granted a four-month reduction.

The trio and the other four defendants were allegedly placing bombs in the men's washroom of Caritas Medical Centre and at Lo Wu MTR Station in 2020, with no one injured.

​Chan said the three's acts were like "declaring war against society", as their long-standing criminal offense became increasingly escalating, including their further plans to place a bomb containing 20 kilograms of a pyrotechnic composition "flash powder" in a car park in Tseung Kwan O.

He also pointed out that their bomb plan in Tseung Kwan O has immense power, endangering not only police nearby but also neighboring residents, describing them as "regarding human life as worthless".

The Judge agreed with the psychological report that Ho has shown no remorse over the past five years since his arrest. The report states that his remorse stems from his inability to escape punishment, rather than the panic and harm he has caused to society. 

The report also stated that Lee insisted that the bomb involved only produced smoke, not explosions or widespread fires, while Cheung maintained that he had nothing to do with the incident. The Judge believed that their remorse was limited.

(Read more: Three convicted, five acquitted in 2020 bomb plots trial)