1. These were appeals against sentences of imprisonment imposed by the Court of Appeal, in place of community service orders originally imposed by the trial magistrate on the appellants, following a review of sentence pursuant to section 81A of the Criminal Procedure Ordinance (Cap. 221) (“CPO”). 2. The appellants had been convicted of unlawful assembly contrary to section 18(3) of the Public Order Ordinance (Cap. 245). The convictions arose from a protest that took place outside the Legislative Council (“LegCo”) on 13 June 2014 against development works in the North East New Territories New Development areas. At around 8:45pm, while LegCo’s Finance Committee was in session, the appellants, who were amongst protesters in the designated demonstration area, rushed towards the entrances of the LegCo building and used Mills barriers, bamboo poles and metal bars to batter and to try to prise open the locked doors in order to force their way in. As a result of this violent unlawful assembly, a security officer was injured and damage was caused to the LegCo facilities which cost over HK$400,000 to repair. 3. At the conclusion of the hearing, the Court of Final Appeal (“the Court”) allowed the appeals and set aside the sentences of imprisonment imposed by the Court of Appeal. The Court, however, did not reinstate the magistrate’s community service orders but instead proceeded to sentence the appellants to terms of imprisonment equal to the length of time each had already been in prison, which ranged from 3 months and 9 days to 5 months and 24 days. 4. In its Reasons for Judgment, the Court concluded that the magistrate erred in principle in imposing community service orders on the appellants because he effectively ignored the element of violence involved and also their lack of genuine remorse. Also, given the scale of the violence involved, the magistrate’s sentences of community service orders of between 80 and 150 hours were manifestly inadequate. The Court of Appeal was therefore entitled to increase the sentences on review. The appropriate sentences in the present case would be custodial sentences rather than community service orders. 5. However, as was accepted by the Director of Public Prosecutions on behalf of the respondent, it was clear that the Court of Appeal could only have imposed sentences with a 15-month starting point by retrospectively applying the new sentencing guidelines laid down by it in Wong Chi Fung for unlawful assemblies involving violence. This was wrong in principle, as the Court of Final Appeal had laid down in Wong Chi Fung, and so the appeals must be allowed and the sentences imposed by the Court of Appeal quashed. 6. Furthermore, section 109A of the CPO required a court not to sentence a young person under the age of 21 to imprisonment unless of the opinion that no other method of dealing with him was appropriate. For the purposes of section 109A, it was the person’s age at the time he was sentenced to imprisonment that was strictly relevant. However, although the 5th and 6th appellants were both 21 years old when sentenced to imprisonment by the Court of Appeal, given that they had passed the threshold age of 21 after committing the offences, the Court of Appeal should have had regard to the conceptual approach laid down in section 109A and imposed sentences on them that were in substance much the same as those which would have been imposed on an offender aged just under 21. 7. As to the disposition of the appeals, it was necessary for the appellants to be re-sentenced on the basis of the sentencing regime for the offence of taking part in an unlawful assembly in accordance with the pre-Wong Chi Fung guidelines. Although this would usually be done by the Court of Appeal as a sentencing court, the Court of Final Appeal itself had jurisdiction to re-sentence and would do so here. 8. On the applicable pre-Wong Chi Fung guidelines, none of the appellants would have been sentenced to more than 6 months’ imprisonment. Given the normal discount when a sentence was increased on review and also allowing for time off for good behaviour, the periods of imprisonment already actually served by each of the appellants (which varied only because of the different dates on which each applied for bail) were such that none of the appellants should now be required to return to prison. Accordingly, they would be sentenced to terms of imprisonment equal to the length of time respectively served by each.