A man was jailed for 10 months on Thursday for writing graffiti on the back of bus seats found to be seditious under the new domestic security law.

Chung Man-kit, 29, pleaded guilty to three counts of “doing an act or acts with seditious intention” under the Safeguarding National Security Ordinance.

The West Kowloon Court heard that he wrote messages threatening national security and advocating "Hong Kong independence" on three occasions between March and April.

Chief Magistrate Victor So said the slogans were visible to the public, even though they were written on the back of the seats, and that society would fall into chaos if he wasn’t stopped.

"He targeted public transportation and chose the upper level and seats at the back of the bus. This was to avoid being easily spotted by bus staff, but at the same time be visible to passengers on public transportation, thus spreading messages promoting Hong Kong's independence and endangering national security," So wrote in a judgement.