A man who was among 12 crime suspects caught during an attempt to travel to Taiwan by speedboat in 2020 was jailed for three years and 10 months by the District Court on Tuesday.

Tang Kai-yin, 34, had earlier admitted perverting the course of justice through the escape bid, as well as possessing articles with intent to destroy or damage property during the 2019 protests.

In sentencing, judge Ernest Lin said the defendant was the ringleader when it came to both offences.

Lin said there was no way that Tang and several others didn't know that the materials for making petrol bombs they had in their possession could seriously injure people, and the only conclusion that could be made is that they were trying to cause chaos and confront the police during the social unrest.

The judge added that Tang had bought the speedboat involved in the attempt to flee to Taiwan, and despite not having a licence or any experience in navigation, he had arranged the route for the journey.

Lin said the defendant had helped those on board the boat escape criminal responsibility and had put them in danger, as well as other vessels on the sea.

The judge described as "self-inflicted" the three-year prison term Tang served on the mainland after the speedboat was intercepted by the Guangdong coast guard.

While Tang might have made poor decisions amid the heated social atmosphere during the protests, he can't claim to have simply been young and naive, Lin added.

The judge gave Tang 34 months behind bars for possessing the petrol bomb materials and 12 months for organising the escape bid, with the two terms to be served consecutively.