Chief Justice Cheung: 1. I agree with the judgment of Mr Justice Lam PJ. Mr Justice Ribeiro PJ: 2. I agree with the judgment of Mr Justice Lam PJ. Mr Justice Fok PJ: 3. I agree with the judgment of Mr Justice Lam PJ. Mr Justice Lam PJ: 4. In HKSAR v Lo Kin Man[1], this Court expounded at length on the law relating to the offences of unlawful assembly and riot under Sections 18 and 19 of the Public Order Ordinance (“the POO”) Cap 245. In respect of the “taking part” in an unlawful assembly, it was held that a defendant must have a participatory intent[2]. The present appeal addresses how such requirement is to be applied when a defendant was one of the persons who committed the prohibited conduct specified in Section 18(1) which rendered the assembly unlawful[3]. The incident 5. The relevant parts of the incident leading to the arrest and prosecution of the Respondent were captured on video recordings produced at the trial and there is no serious dispute on the facts. It took place at a time when the doxxing of police officers was a serious problem and the courts had to intervene by granting injunctions against such activities[4]. 6. On 8 March 2020, a police officer (“PW1”) was on plainclothes duty near Tai Po Mega Mall. At around 9:40 p.m. he was approached by a person[5] demanding that PW1 reveal his identity as a police officer. PW1 did not reply. Thereafter, that person spoke with a co-defendant, viz the 4th defendant, informing the latter that PW1 was a police officer[6]. PW1 was then tailed by the 4th defendant and several other persons. Some of them came close to PW1 from time to time whilst most of them kept their distance. There were people shouting his name and the names of his wife and daughter. There were also repeated accusations that he had previously beaten up a youngster with a baton. Denigrating and threatening remarks were made against him. PW1 left the mall and walked in the direction of Tai Po Police Station. 7. After PW1 had come out from the mall, four people including the Respondent rushed to where he was and trailed closely behind him. As he did so, the Respondent used a video camera continuously to make a recording. There were other people following a further distance away. Amongst the four who were trailing closest to PW1, two of them flashed their torches at him. At one stage, the flashes aimed at PW1’s head and the Respondent overtook PW1 to film his face whilst the others shouted PW1’s name and accused him of the beating of a youngster. In addition to those four persons, those following behind also came closer and the group of people around PW1 increased. 8. Subsequently, other police officers arrived and arrests were made. The Respondent and four other persons were charged with the offence of unlawful assembly. The Respondent pleaded not guilty. His defence was that there was no unlawful assembly and that he did not participate in any assembly. His counsel submitted that the Respondent only filmed the incident spontaneously without any ill intent on his part. The proceedings below and leave to appeal 9. After trial, Principal Magistrate Don So (“the magistrate”) found the Respondent guilty and imposed a sentence of 3 months’ imprisonment on him. The magistrate decided the case without the benefit of this Court’s judgment in HKSAR v Lo Kin Man as that appeal was only heard after his decision. Although PW1 was first approached by a person asking if he was a police officer about 6 minutes prior to the commencement of the filming by the Respondent, the magistrate focused on the conduct of the parties, which lasted about 2 minutes, as shown in the recording made by the Respondent. The magistrate found that the Respondent and three other defendants[7] had assembled together[8] and their acts insulted and provoked PW1. Such acts included the Respondent’s filming which targeted PW1 most of the time and were likely to cause other persons reasonably to fear that those assembled would commit a breach of the peace or provoke other persons to commit a breach of the peace[9]. He also found that cumulatively these acts had a greater intimidating effect. He held that the respective act of the 2nd to 4th defendants, and that of the Respondent, constituted prohibited conduct under Section 18(1) of the POO. 10. In rejecting the Respondent’s defence, the magistrate found that he had consciously assembled with the other three defendants. He noted that there was no suggestion that the Respondent was a reporter but that he was able to film the incident without fear of assault or other hostile responses by the 4th defendant. He inferred that there was a consensus between the Respondent and the 4th defendant that the recording would not be voluntarily produced as incriminating evidence. He further found that the Respondent was aware of the harassment, threat and provocation directed towards PW1 at the scene and that he deliberately participated in the assembly[10]. 11. On appeal to the Court of First Instance, A Wong J (“the Judge”) allowed the Respondent’s appeal against conviction. The Judge rejected the contention that the filming of PW1 by the Respondent did not come within the scope of prohibited conduct under Section 18(1) of the POO[11]. Having regard to the circumstances surrounding the Respondent’s filming, the Judge upheld the magistrate’s finding that such conduct was provocative. 12. The Judge also agreed with the magistrate in finding that the Respondent was aware of the acts of the other defendants[12] and that the conduct of the Respondent had the effect of procuring or encouraging the other defendants to commit their prohibited acts[13]. He noted that there was an unlawful assembly with more than 3 persons (including the Respondent) committing prohibited conduct and the Respondent’s filming took place against such backdrop when he was “well aware of the actual situation at the scene”[14]. 13. The Judge affirmed the finding that the 4th defendant permitted or acquiesced in the Respondent’s filming which recorded the commission of the offence by the 4th defendant. However, he did not accept that the only reasonable inference was that there was a consensus between the Respondent and the 4th defendant. The Judge also declined to assess the matter on the basis that the Respondent had targeted PW1 in his filming though he considered the magistrate was justified in so holding[15]. 14. By the time the Judge heard the appeal, this Court had delivered its judgment in HKSAR v Lo Kin Man. The Judge referred to the law set out in that judgment[16] and he discussed the issue of participatory intent in light of it [17]. After considering various matters which he regarded as relevant, the Judge concluded that though it was a reasonable inference supported by the evidence that the Respondent had the requisite participatory intent, it was not the only reasonable inference[18]. He therefore allowed the appeal by quashing the conviction. 15. The prosecution sought leave to appeal against the Judge’s decision. On 11 July 2022, the Appeal Committee granted leave as it was reasonably arguable that the Judge had misapplied this Court’s judgment in HKSAR v Lo Kin Man and that substantial and grave injustice had been done. Lo Kin Man’s exposition of unlawful assembly 16. Section 18 of the POO codified the offence of unlawful assembly. In HKSAR v Lo Kin Man[19], the elements of the offence were set out as follows: “[1] When 3 or more persons, [2] assembled together, [3] conduct themselves in a disorderly, intimidating, insulting or provocative manner [4] intended or likely to cause any person reasonably to fear that the persons so assembled will commit a breach of the peace, or will by such conduct provoke other persons to commit a breach of the peace, [5] they are an unlawful assembly. [section 18(1)] [6] It is immaterial that the original assembly was lawful if being assembled, they conduct themselves in such a manner as aforesaid. [section 18(2)] [7] Any person who takes part in an assembly which is an unlawful assembly by virtue of subsection (1) shall be guilty of the offence of unlawful assembly ... [section 18(3)]” 17. The offence-creating provision is Section 18(3) and the essence of the offence is the “taking part” in an unlawful assembly[20]. Such “taking part” may or may not involve the same acts as, and should not be confused with, the prohibited conduct of the constituent offenders referred to in elements [3] and [4]. 18. Constituent offenders are those who assemble together and conduct themselves in the manner described in element [3]. Because of their conduct, the assembly is unlawful[21]. For these offenders, their “taking part” is self-evident: “If the defendant was one of the constituent offenders, by engaging in the prohibited conduct, he or she will (along with other constituent offenders) have taken part in the unlawful assembly that they will together have brought into being.”[22] “As a matter of textual analysis, it is implicit that if the defendant is one of the constituent offenders whose conduct falls within [3] and [4] he or she would ‘take part’ since it is by such acts that the unlawful assembly is established, being of the essence of the offence.”[23] 19. For persons other than the constituent offenders, viz those who took part later, they could participate by acting in the manner prohibited by elements [3] and [4][24]. Alternatively, they could also participate by facilitating, assisting or encouraging the performance of such conduct by others in the assembly[25]. In so doing, they acted in furtherance of the prohibited conduct[26]. 20. This Court also alluded to element [6] which underscores that an assembly could be transformed from a lawful one to an unlawful one[27]. It is only the participation in an unlawful assembly which constituted an offence. The participation in a lawful assembly is not an offence as freedom of assembly is a fundamental right protected under Article 27 of the Basic Law. 21. As discussed in earlier cases[28], the fluidity of an assembly has to be borne in mind. People who participate in a lawful assembly which subsequently develops into an unlawful one should not be found guilty if they do not take part in the unlawful assembly. Thus, this Court emphasized: “It is obviously important to avoid treating innocent passers-by who find themselves caught up in an unlawful assembly or riot as guilty of an offence just because they were present at the scene. Presence at the scene in itself is not enough to constitute ‘taking part’ or aiding and abetting. As the Queensland Court of Appeal held in R v Cook, at common law, mere presence in an unlawful assembly or riot is generally insufficient to found liability. It has traditionally been considered necessary that there be some intentional activity in furtherance of the riot.”[29] (footnotes omitted) 22. On the other hand, if some latecomers to a lawful assembly conduct themselves in the manner prohibited by Section 18(1), they could turn the assembly into an unlawful one and they would be the constituent offenders. Those in the assembly who continue to take part in it after such transformation would be guilty under Section 18(3). Moreover, even if the constituent offenders leave the scene after committing the prohibited conduct, the unlawful assembly continues so long as three or more participants in the assembly remain actively engaged in such conduct[30]. 23. Whether those who remain in the assembly after its transformation into an unlawful assembly can be regarded as taking part in the unlawful assembly depends on their continued participation in the assembly with a participatory intent. This Court stressed that mere presence without more would not be regarded as taking part[31]. 24. The requirement of participatory intent is neatly summarized in HKSAR v Lo Kin Man: “The defendant must accordingly intend to take part in, that is, become part of, the unlawful assembly, being aware of the related conduct of other participants and intending, while assembled together with them, to engage in or act in furtherance of the prohibited conduct. The defendant must, in other words, have what we will call a ‘participatory intent’.”[32] 25. Two ingredients were set out in that paragraph: (a) the defendant intended to become part of the assembly; and (b) while he or she assembled together with these other participants and was aware of the related conduct of other participants, he or she intended to engage in or act in furtherance of the prohibited conduct. 26. Ingredient (a) refers to the intention to become part of an assembly, whilst ingredient (b) refers to the mental state of the defendant in acting in the way he did when he participated. 27. The intention to become part of an assembly corresponds with the actus reus of the defendant in acting as part of the relevant assembly[33]. Thus, as held in Secretary for Justice v Leung Kwok Wah: “... if three persons in a lawful assembly committed acts of the prescribed nature at different parts of the place of assembly for different purposes, sparking off different incidents, involving and affecting an entirely different mix of persons, there would not be a sufficient nexus to turn these independent acts into an unlawful assembly of those three persons.”[34] (footnote omitted) 28. Conversely, if a defendant was in proximity to the other participants who committed prohibited acts and, whilst being aware of such conduct, the defendant joined in by committing further act or acts, a sufficient nexus could readily be established. The prohibited acts of different participants could be different in nature but they must satisfy the requirement of element [3]. Since they committed these acts in the same assembly, the intended or likely fear of a breach of the peace by mob disorder, intimidation or violence under element [4] is enhanced. As observed in R v Caird[35], the gravity of this type of offence stems from the number of people involved as a mob engaged in a crime against the peace and it is the degree of mob disorder, intimidation or violence that matters. It is a wrong approach to treat different acts of provocation or intimidation in an assembly as isolated conduct in such circumstances. 29. As far as ingredient (a) is concerned, it suffices that a defendant has the intent to become part of the assembly. It is not necessary to show that such defendant has the intention to take part in each and every act of the other participants. The intent to participate in specific act or acts in the assembly is to be considered under ingredient (b). 30. In respect of ingredient (b), a defendant has to be aware of the prohibited conduct which rendered the assembly unlawful or the further prohibited conduct which continued the unlawful character of the assembly. With such knowledge, the requisite mental state can be satisfied in two different ways: by showing either (i) an intention to engage in the prohibited conduct or (ii) an intention to act in furtherance of the prohibited conduct. Such alternatives in establishing the mental element mirror the conduct of a defendant that constitute “taking part” in the assembly, viz by either engaging in prohibited conduct or acting in furtherance of such conduct by facilitating, assisting or encouraging the conduct of the others in the assembly. 31. This Court also held that the prosecution needs not establish any extraneous common purpose amongst the participants[36]. In so holding, this Court specifically rejected an additional “mutual assistance” element and answered Question 1(d) in the negative[37]. 32. Further, this Court held that it would be confusing to apply the doctrine of basic joint enterprise in the context of unlawful assembly. It emphasized that it was not necessary to show a prior agreement between the participants: “Their participatory intent would be inferred from their prohibited conduct while assembled together, so from the prosecution’s viewpoint, invoking the BJE doctrine would add the unwarranted burden of showing a prior agreement. From the Trial Judge’s point of view, jettisoning BJE in this context would avoid possibly confusing the jury by trying to explain two layers of ‘taking part’ – first in the joint enterprise and then in the unlawful or riotous assembly.”[38] The constituent offenders in the present case 33. Though PW1 was first approached about 6 minutes prior to when the Respondent started his filming of the incident, there was no suggestion or finding that there was an unlawful assembly during those 6 minutes. In my view, the magistrate correctly focused on the events captured in the Respondent’s recording. That was the stage at which 3 or more persons acted together in the close vicinity of PW1 and behaved in the manner prohibited by Section 18(1). Whilst there were earlier acts of flashing light and accusations directed at PW1 with another person making a video recording, such footage did not evidence conduct committed by 3 or more persons acting together in those instances. 34. In short, for present purposes, the unlawful assembly only came into being after the Respondent had joined the other defendants in the group trailing closely behind PW1. The Respondent was one of the constituent offenders in the unlawful assembly. 35. The finding of the magistrate was that the Respondent had committed the prohibited conduct by filming when he was with the other defendants. The Judge upheld such finding as he rejected the ground of appeal concerning the nature of his conduct. Thus, the Respondent participated in the assembly by committing a prohibited act. Ingredient (a): the Respondent’s intent to become part of the assembly 36. The magistrate specifically found that the Respondent had assembled with the other defendants. Though the Judge reversed the magistrate on participatory intent, he did not do so on the basis that there was an insufficient nexus between the Respondent and the other defendants. On the contrary, he found that the Respondent had run to the place where others were assembled[39] and had engaged in the filming, well aware of the actual situation at the scene[40]. 37. These findings are well-supported by the video recordings produced as evidence at the trial. The Respondent was seen to be rushing towards PW1 together with others in the group[41] shortly after the 4th defendant flashed his torch at PW1 inside the mall. Moreover, as found by the magistrate (and affirmed by the Judge), the Respondent was able to do the filming without objection or fear of reprisal by the others in the group. Thus, the magistrate was justified in drawing the inference that the Respondent was acting together with the other defendants. In other words, he had the intent to become part of the group of people who pestered PW1 at close distance. 38. Mr Choy SC[42] submitted on behalf of the Respondent that the Judge had adopted the approach suggested by this Court in HKSAR v Lo Kin Man[43] and came to the conclusion that he could not draw an irresistible inference that the Respondent had the intention to participate after considering a list of 19 factors. Counsel said the Judge was obliged to examine the matter by way of rehearing and this Court should not interfere with his assessment. 39. As explained in HKSAR v Lo Kin Man, circumstantial matters should be taken into account in the determination of whether a defendant had taken part in an unlawful assembly or a riot. However, the relevance of each matter must depend on the facts of each case. 40. The Judge did not reverse the finding that the Respondent had joined the others in the assembly. He also accepted that the Respondent was aware of the related conduct of the other defendants and that his provocative filming of PW1 was done against the backdrop of the unlawful assembly. 41. In the consideration of his list of 19 factors[44], the Judge veered away from asking whether the Respondent had the intent to become part of the assembly. Instead, he proceeded to examine if the Respondent had the requisite intent of procuring or encouraging the other defendants to perform their prohibited conduct[45]. Thus, he laid emphasis on certain factors including his reservation regarding the finding of the magistrate as to consensus with the other defendants, the different nature of the conduct of the Respondent and his lack of communication with the others. 42. With respect, in doing so in a case where the participation was by committing a prohibited act, the Judge failed to have regard to the following propositions laid down in HKSAR v Lo Kin Man: (a) The prohibited act of one participant could be different from that committed by another participant; (b) There is no need to prove an agreement or consensus on the part of a defendant with the other participants in the commission of their prohibited conduct; (c) There is no need to prove an intention to offer mutual assistance to one another in the commission of the prohibited conduct. 43. Had the Judge properly focused on the Respondent’s intent to become part of the assembly, notwithstanding those factors he alluded to, the inescapable conclusion would have been that the Respondent had joined the assembly for the reasons already canvassed above[46]. Ingredient (b): the intent of the Respondent in his acts of participation 44. As the Respondent participated by committing a prohibited act, his participatory intent can be established by reference to his intention to engage in such act while assembled with the other defendants. There is no doubt that he was aware of the related conduct of the other participants. Likewise, there is no doubt that he intended to engage in his filming of PW1. As held in HKSAR v Leung Chung Hang Sixtus[47], it is not necessary to prove in addition that the Respondent intended his act to be provocative in nature. The submission to the contrary by Mr Choy SC is without merit. 45. Though the Judge had previously acknowledged that the magistrate had found the Respondent guilty on the basis that he was a constituent offender[48], it is not clear whether the Judge had regard to such finding in his assessment of participatory intent. 46. As explained above[49], it is not necessary in the present case for the prosecution to prove an intent on the part of the Respondent to act in furtherance of the prohibited conduct of the other defendants. In other words, there is no need to show that by his filming of PW1 the Respondent intended to facilitate or encourage the other defendants in committing their prohibited conduct. 47. Had the Judge properly directed himself as to the Respondent’s participation by committing a prohibited act and the requirement of participatory intent as discussed above, the matters which he relied upon should not have precluded him from drawing an irresistible inference that the Respondent had the intent to commit the prohibited act. This is clearly not a case of mere presence or spontaneous filming by an innocent bystander. Conclusion 48. The Judge misapplied the law as stated in HKSAR v Lo Kin Man and the quashing of the conviction therefore resulted in substantial and grave injustice. I would allow the appeal and restore the conviction and sentence against the Respondent. Lord Hoffmann NPJ: 49. I agree with the judgment of Mr Justice Lam PJ. Chief Justice Cheung: 50. Accordingly, the Court unanimously allows the appeal and restores the conviction and sentence against the Respondent. Mr Ivan Cheung, ADPP (Ag) and Ms Jennifer Tsui, SPP (Ag), of the Department of Justice, for the respondent (appellant) Mr Edwin Choy, SC, Mr Brian Tsui and Mr Jonathan Lin, instructed by Chak & Associates LLP, for the appellant (respondent) [1] (2021) 24 HKCFAR 302. [2] Ibid, [17], quoted at [24] below. [3] Ibid, [9]. [4] See Secretary for Justice v Persons Unlawfully and Wilfully Conducting Etc (1957/2019) [2019] 5 HKLRD 500; Junior Police Officers’ Association of the Hong Kong Police Force v Electoral Affairs Commission [2019] 5 HKLRD 291 and Secretary for Justice v Persons Unlawfully and Wilfully Conducting Etc (1847/2020) [2020] 5 HKLRD 638. Even after the grant of injunctions, there were people continuing in such activities and contempt proceedings had to be pursued, see Secretary for Justice v Cheng Lai King [2020] 5 HKLRD 356; Secretary for Justice v Chan Kin Chung [2021] 1 HKLRD 563; Secretary for Justice v Yiu Ka Yu [2021] 1 HKLRD 607. [5] That person was the 1st defendant in the trial before Principal Magistrate Don So in which the Respondent was the 5th defendant. The 1st defendant did not walk alongside PW1 during the last two minutes of the incident and he was acquitted after trial. [6] Statement of Findings at [11]. [7] The 2nd to 4th defendants in the case. [8] Statement of Findings at [14], [18] to [20]. [9] Statement of Findings at [15] and [16]. [10] Statement of Findings at [18] to [20]. [11] CFI judgment at [37] to [44]. He reiterated this at [45] as the factual basis for his consideration of participatory intent. [12] CFI judgment at [49]. [13] CFI judgment at [47]. [14] CFI judgment at [54(1) to (4) and (10)]. [15] CFI judgment at [51] to [52]. [16] In the CFI judgment, the Judge referred to the judgment as HKSAR v Leung Tin Kei. [17] CFI judgment at [33]. See also [48] where the Judge reiterated that he would rely on his [33] as the basis for his consideration of participatory intent. [18] CFI judgment at [49] to [55]. [19] Supra. at [8]. [20] Supra. at [11]. [21] Supra. at [9]. [22] Supra. at [12]. [23] Supra. at [13]. [24] Supra. at [13]. [25] Supra. at [14]. [26] Supra. at [14] and [109(d)]. [27] Supra. at [10]. [28] Kwok Wing Hang v Chief Executive in Council (2020) 23 HKCFAR 518 at [91] and [92]; Leung Kwok Hung v Secretary for Justice (No 2) [2020] 2 HKLRD 771 at [14]; Secretary for Justice v Tong Wai Hung [2021] 2 HKLRD 399 at [56]. The point was reiterated in HKSAR v Lo Kin Man, supra. at [75] to [78]. [29] Supra. at [81]. [30] Supra. at [77]. [31] Supra. at [85] and [86]. [32] Supra. at [17]. [33] Supra. at [16]. [34] [2012] 5 HKLRD 556 at [21]. Cited in HKSAR v Lo Kin Man at [42]. [35] (1970) 54 Cr App R 499 at 506 to 508. [36] Supra. at [38] to [50]. [37] Supra. at [34] to [35] and [50]. Question 1(d) is as follows: “whether it is a distinct element of riot under Section 19 of the POO that the defendants must have the mutual intention to assist each other, by force if necessary, against any person who might oppose them in the execution of the common purpose?” [38] Supra. at [67]. Basic joint enterprise was defined as BJE and referred to as such in the passage cited. [39] CFI judgment at [54(9)]. [40] CFI judgment at [54(10)]. [41] P18(D) at 21:45:46; P17A at 01:16-01:19; P18(C) at 21:45:51 to 21:46:10. [42] Appearing together with Mr Tsui and Mr Lin for the Respondent. [43] Supra. at [78]. [44] Set out at CFI judgment [54]. [45] CFI judgment at [47]. The original Chinese version of the judgment is clearer than the English translation in this respect. [46] See [36] and [37] above. [47] (2021) 24 HKCFAR 164. [48] CFI judgment at [36]. [49] See [29] to [30] and [44] above.