Ma Chun-man, 31, is the second accused to be sentenced under the new security law imposed by Beijing on Hong Kong on June 30 last year.

In sentencing Ma, a former food delivery worker and activist, District Court judge Stanley Chan Kwong-chi said the case was serious and that Ma had shown no remorse and had repeatedly promoted independence ideas.

Ma was convicted of "inciting secession" over the content of the slogans he chanted and the speeches he made in at least 20 public occasions and via social media between August 15 and November 22 last year.

He used slogans including "Hong Kong independence, the only way out", "Hongkongers build their country" and "Liberate Hong Kong".

Handing down the sentence on Thursday, Chan said Ma viewed his only option in his life was his political mission.

Besides advocating Hong Kong independence, Ma also "unbridled disparaged" the national security law.

Chan said it's not crucial whether the political stance Ma advocated was successful but the key points were his offences and his mens rea.

He said Ma has repeatedly incited others for secession. He also promoted secession in a “layered” plan, and even thought of starting from schools to spread and infiltrate the thought to various levels of society to promote the next revolution.

Ma wrote a mitigation letter on September 28 in which he stated that: “For what I did in the past, I do not feel ashamed and I have no remorse.”

“I also promise that I will not be weak on the path to pursue democracy. From now on, I will do my best and spend all my life to chase the dream I believe in, may glory be to Hong Kong,” he wrote, naming himself "Captain America 2.0".

Chan agreed with the defense that Ma may not completely understand the ins and outs of the complicated social event, but he still incited others.

He also said Ma was prepared and did not commit the offense on impulse, saying he even gave himself a nickname, showing that he was obviously proud of himself.

Chan also cited a psychological report saying Ma was a person being incited at first but he turned into a person who incited others.

Earlier in mitigation, Ma's defense counsel Edwin Choy Wai-bond said his client was lonely and did not have much communication with his family.

He also did not have hobbies and dreams.

He felt that he had connections with others by participating in protests.

Choy said his client deserved a lighter sentence of no more than five years behind bars as his case is not considered serious under the national security law as it did not involve any violent actions.

But Chan disagreed, saying the offense took place on 20 occasions.

He added he decided to use six years’ imprisonment as the starting point but because the defense did not challenge the prosecution on the facts, saving the court's time, he reduced the jail term by three months.

Ma, who wore a light grey jumper, was calm when hearing his sentence in the dock, but a woman in the public gallery shouted: “Too long!”.

Amnesty International’s deputy secretary general Kyle Ward called the sentencing “outrageous”.

“In the warped political landscape of post-national security law Hong Kong, peacefully expressing a political stance and trying to get support from others is interpreted as ‘inciting subversion’ and punishable by years in jail,” he said in a statement on Thursday.