A Hong Kong opposition lawmaker, who was found guilty of desecrating the national flag during protest antics in the legislature, has offered an apology and promised to “make amends” as authorities are vetting his candidacy bid for the coming Legislative Council elections.

Cheng Chung-tai of localist party Civic Passion said in a letter to an electoral official that he had reflected on his antics since the court case, realising it was wrong and that he had since been upholding the Basic Law and showing respect for the national flag.

Cheng is seeking re-election in New Territories West constituency in the Legco polls, expected to be held on September 6.

On October 19, 2016, lawmakers from the pro-establishment Democratic Alliance for the Betterment and Progress of Hong Kong put the miniature national and Hong Kong flags on their desks in the chamber, to protest against several pro-independence members’ bids to retake their oaths, which had previously been ruled invalid.

Cheng upended the flags after the pro-government members left the chamber to prevent the retaking.

He argued at the time that his intention was to poke fun at the rival camp for their “cheap display of patriotism”.

In a 2017 court ruling, Cheng was found guilty of desecrating the national and Hong Kong flags, and fined HK$5,000 (US$645). He subsequently lost his teaching job at Polytechnic University in 2018 as a result of disciplinary action related to his conviction.

In a letter dated on Tuesday to returning officer Janet Wong Chin-kiu, Cheng wrote: “I offer my apology. I will make amends and will continue upholding the Basic Law, and cherish the national flag.”

He also declared that he “absolutely” did not support Hong Kong independence.

During his four-year term, Cheng was regarded as an independent opposition lawmaker who kept a distance from both the traditional pan-democrats and other localist lawmakers who resorted to more confrontational antics in the chamber.

His party, Civic Passion, declined to participate in the opposition camp’s unofficial primary earlier this month.

Separately, activist Lester Shum, who hopes to stand in the district council (second) constituency, was also questioned by authorities about his political views. In his reply, he said he no longer wanted to demand foreign countries’ sanctions on Hong Kong.

On his criticisms against the national security law, the former student leader said he agreed Hong Kong had a constitutional duty to safeguard national security, but was opposed to the form of the legislation imposed on the city by Beijing.