A 13-year-old Hong Kong girl who admitted burning the Chinese flag during a protest “out of impulse” was sentenced to 12 months’ probation by a court on Friday.

The sentence at Tuen Mun Court meant the Form Two student, who could not be named for legal reasons, would be left with a criminal record, after she committed the offence during a demonstration approved by police on September 21.

The girl’s lawyer Douglas Kwok King-hin had urged the court to exercise its discretion and give the girl one more chance by passing a sentence that would maintain her clear criminal record.

But magistrate Kelly Shui accepted the recommendation made by the girl’s probation officer and sentenced her to probation. She told the pupil: “The court cannot pass a lenient sentence every time because you are young. The court has its duties.”

The girl was the second Hong Kong protester to be convicted of desecrating the national flag, and by far the youngest to plead guilty to flag-related charges during the anti-government protests that had gripped the city for over half a year.

The court heard at 3.43pm that day, the girl and two unknown protesters had pulled down the national flag outside Tuen Mun Town Hall. She then set fire to the flag with a lighter.

The incident was captured by the press, allowing police to identify the girl. Officers followed the girl to a shopping centre in Sham Tseng and arrested her, according to prosecutors.

At the previous hearing on November 22, Kwok told the court the girl had no premeditated plan to burn the flag, but was caught up in the march and influenced by other protesters.

He also said the girl and her parents had been subjected to harassment online and she had received anonymous threats of rape, kidnap and even murder. She did not dare to take part in other public events, the lawyer added.

On Friday, Kwok said the girl had a “detailed” discussion with the probation officer, who was satisfied that a probation period could help correct her impulsive behaviour. He submitted two letters written by her school principal and football coach, who described her as a student of good conduct.

In passing the sentence, Shui reminded the girl to think twice every time before she acted. She also warned that the girl might face jail the next time she committed a more serious offence.

“The social movement currently has no end in sight … You may be swayed one way or another by others. This is very dangerous,” Shui said. “You should not be ignorant of the fact that some people have lost their freedom over their convictions.

You don’t want that to happen to you as well.”

Shui also ordered the girl to follow the order of the probation officer in participating in community work, group counselling and rehabilitation programmes. The girl must also obey a curfew between 7.30pm and 7am every day, unless she went out at night in her parents’ company or otherwise permitted by the officer.

Desecrating the national flag is a crime punishable by three years in prison plus a HK$50,000 (US$6,400) fine. Sentencing in magistrates’ courts, however, is capped at two years in jail.

On October 29, Sha Tin Court spared jail for Law Man-chung, 21, who was the first to plead guilty to desecrating the national flag during an anti-government protest. Law was sentenced to 200 hours of community service.

The Department of Justice lodged an appeal against Law’s sentence on November 14. The High Court will hear the appeal at a later date.