A Hong Kong court has sentenced three people to prison terms of up to 18 years over three bomb plots in 2019 and 2020.

Lukas Ho, 41, on Monday received an 18-year sentence, with Judge Johnny Chan saying he had an “inflated ego” and showed no remorse, which posed a “risk to public safety”.

Chan said Ho was the mastermind, showed no remorse, and had no grounds for a reduced sentence. Lee and Cheung, he said, were first-time offenders, and were each granted a four-month reduction.

“The court must provide sufficient deterrence, so the need for defendant’s rehabilitation is less important than the former point,” Chan said.

“Also, if remorse is limited or superficial, there’s no way to talk about rehabilitation and correction.”

Ho’s co-defendants, Lee Ka-pan and Cheung Ka-Chun, each received jail terms of 16 years and eight months.

The three men remained impassive during sentencing and smiled to friends and family in the public gallery as they were led away by guards.

The trio was part of a group charged in relation to a homemade bomb that went off in a hospital toilet in January 2020, and explosive devices found at a railway station the following month.

The two incidents caused no casualties.

The court previously heard the plot was part of an attempt to force authorities to shut Hong Kong’s borders in the early days of the pandemic, when the coronavirus was spreading in neighbouring mainland China.

A jury acquitted five other people in the same case last month.