NOISE CONTROL AUTHORITY AND ANOTHER v. STEP IN LTD

FACV No. 11 of 2004

IN THE COURT OF FINAL APPEAL OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

FINAL APPEAL NO. 11 OF 2004 (CIVIL)

(On appeal from CACV NO. 302 of 2003)

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J U D G M E N T

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Chief Justice Li :

1.  I agree with the judgment of Sir Gerard Brennan NPJ.

Mr Justice Bokhary PJ :

2.  I entirely agree with the judgment of Sir Gerard Brennan NPJ which I have had the benefit of reading in draft.  All that I would add in words of my own are a few observations on legal certainty.  Objection can be taken on constitutional grounds to any law, regulation or administrative action that creates a state of uncertainty in which persons are inhibited from enjoying their fundamental rights and freedoms in full measure.  But playing loud music is not a fundamental right or freedom.  And the law does not accord it precedence over the peace and quiet that people can reasonably expect to enjoy.  This case is about low frequency noise transmitted through the structure of a building so as to disturb the sleep of occupants.  The uncontradicted evidence is that such noise cannot be effectively controlled through a decibel-based noise limit.  So the protection of occupants requires inaudibility at the nearest noise sensitive receiver.  To ensure that he complies with such a requirement, a noise-maker may have to steer well away from the line between legality and illegality.  That is unfortunate.  But it is unavoidable.  And it is acceptable since no constitutional right or freedom is adversely affected in any way. 

Mr Justice Chan PJ :

3.  I agree with the judgment of Sir Gerard Brennan NPJ.

Mr Justice Ribeiro PJ :

4.  I agree with the judgment of Sir Gerard Brennan NPJ.

Sir Gerard Brennan NPJ :

5.  Knutsford Terrace in Tsimshatsui contains several bars and restaurants, and is an entertainment as well as residential area.  One of the bars, known as “Chasers” is conducted by the respondent, Step In Limited (“the Operator”).  Chasers is on the ground floor of the Carlton Building, the upper floors of which are occupied as residences.  The occupant of the flat above Chasers complained to the Noise Control Authority (“the Authority”) about the noise emanating from Chasers.  Occupants of other flats also complained about that noise.  A band plays in Chasers during the night for the entertainment of its patrons.  The Authority, which is constituted pursuant to the Noise Control Ordinance, Cap. 400, served the Operator with a noise abatement notice which is known as a “NAN” on 2 April 2002.  The NAN was varied on 28 November 2002.  The serving of a NAN is provided for by s.13 of the Noise Control Ordinance.  The relevant provisions of s.13 are as follows:

"(1) Where the Authority is satisfied that noise is emanating from any place other than domestic premises, a public place or a construction site and that such noise, whether on its own or together with noise emanating from any other place other than domestic premises, a public place or a construction site, -

(a) is a source of annoyance to any person (other than a person in the place from which the noise is emanating) in any place considered to be a noise sensitive receiver in any Technical Memorandum issued under section 10;

(b) does not comply with any standard or limit prescribed for the purposes of this section; or

(c) does not comply with any standard or limit contained in Technical Memoranda issued from time to time under section 10(1),

the Authority may serve a noise abatement notice in the prescribed form on any or all of the following -

(i) the person making the noise or causing or permitting the noise to be made; or

(ii) the owner, tenant, occupier or person in charge of the place from which the noise is emanating.”

6.  There has been no challenge to the authority of the Authority to serve a NAN on Chasers.  The NAN recited the Authority’s satisfaction that “the noise emanating from the activities, including playing or operating any musical or other instrument and playing amplified music in Chasers … was a source of annoyance to the nearby Noise Sensitive Receivers”.  Section 13(1)(a) was the ground assigned for serving the NAN.  The litigation which followed relates to the requirements specified by the NAN, a matter governed by the provisions of subsections (2) and (3) of s.13, which read as follows:

“(2) A noise abatement notice served under subsection (1) relating to noise emanating from any place may require the person on whom it is served to abate the noise within the period specified therein and to do all things as may be necessary for that purpose, and may require the person on whom it is served to -

(a) ensure that the noise emanating from such place does not exceed any limit or standard specified in the notice;

(b) where the noise is emanating from such place by reason of the operation of any plant, machinery, vehicle, equipment or process, ensure that any such plant, machinery, vehicle, equipment or process is operated in accordance with any condition specified in the notice; and

(c) notify the Authority in writing within the period specified in the notice that any requirement referred to in paragraph (a) or (b) and specified in the notice has been complied with.

(3) In specifying a period under subsection (2) within which noise is to be abated, the Authority shall have regard to the nature, difficulty and complexity of complying with any requirement in the noise abatement notice.”

7.  The requirements which a NAN may prescribe must be directed to abating “the noise”, that is, the noise described in subsection (1).  It is the noise which emanates from the particular premises and which is – relevantly to the present case – a source of annoyance to the complainants in the upper floors of the Carlton Building.  An “annoyance” is defined by s.2 to mean an “annoyance that would not be tolerated by a reasonable person”. 

8.  The Ordinance confers on the Authority a choice as to the form in which a NAN is expressed: a NAN may require simply an abatement of the noise or it may require both an abatement and conduct “to ensure that the noise emanating from [the particular] place does not exceed any limit or standard specified in the notice”.  Subsection (2) is in terms similar to s.80(1) of the Environmental Protection Act 1990 (UK) which was held to allow a Health Authority to choose the form of an abatement notice requiring either an abatement of a specified nuisance or an abatement together with the execution of works as a means of effecting the abatement: see R v. Falmouth and Truro Port Health Authority, ex parte S W Water Ltd [2001] QB 445. 

9.  Non-compliance with the requirements of a valid NAN is an offence.  Subsections (6) and (7) so provide:

“(6) Any person who, having been served with a noise abatement notice under subsection (1) or a notice under subsection (4), fails to comply with any requirement therein commits an offence.

(7) Any person who commits an offence under subsection (6) shall be liable -

(a) on first conviction to a fine of $100,000;

(b) on second or subsequent conviction, to a fine of $200,000,

and in any case to a fine of $20,000 for each day during which the offence continues.”

10.  The original NAN required the Operator to abate the noise complained of “within the period from 2 May 2002 to 1 June 2002” (inclusive) and to “ensure that at anytime within 6 months commencing on 2 June 2002 the noise emanating from activities, including voices, playing or operating any musical or other instrument and playing amplified music, in the … premises comply with the noise limits when assessed at the assessment points during the time periods specified in Table 1 of the attached Annex under s.13(2)(a)” of the Ordinance.  The varied NAN substituted 12 months for the 6 months originally specified.  For the purposes of this appeal, nothing turns on the variation, or on the requirement to abate the noise on or before 1 June 2002.  Table 1 of the annex attached to the NAN read as follows:

Time Period	Noise Limits
	Indoor	Exterior of Building Facade
Day & Evening (0700 – 2300 hours)	Not exceeding 55 dB(A)	Not exceeding 65 dB(A)
Night (2300 – 0700 hours)	Not audible	Not applicable

 

11.  The specified “indoor” limits were to be assessed “at a position 1.2 metres above floor inside the nearest Noise Sensitive Receivers in Carlton Building”.  The nearest “Noise Sensitive Receiver” was the domestic flat in the Carlton Building nearest to Chasers.  Domestic premises are considered to be a Noise Sensitive Receiver pursuant to s.2.2 of the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites issued under s.10(1) of the Ordinance, hereafter the “Technical Memorandum” or “TM”.  The outdoor assessment point was one metre from the exterior of the building facade of the same flat. 

12.  The Operator was concerned by the requirement expressed in the words “not audible” as a noise limit for the night hours 2300 – 0700 hours set out in the Table to the NAN.  By an Amended Notice of Appeal dated 11 July 2002 the Operator appealed to the Noise Control Appeal Board (“the Board”) against that part of the NAN which imposed an indoor noise limit of “not audible” for the specified period. 

13.  The grounds of appeal stated by the Operator were that the “not audible” requirement was –

"(a) ultra vires the Noise Control Ordinance and/or

(b) not a lawful ‘limit’ within s.13(2)(a) of the Ordinance and/or

(c) excessively subjective and therefore uncertain and/or unreasonable in character or extent and/or

(d) not capable of objective compliance or attainment and therefore void and uncertain."

A ground of “economic hardship” which had appeared in an earlier Notice of Appeal was omitted from the Amended Notice. 

14.  In submissions before the Board, the Operator submitted, inter alia, that a NAN which specified a limit expressed in decibels weighted to reflect auditory response to different frequencies (dB(A)) would have been within power, but the “not audible” limit was not.  It was too uncertain in content.  The Operator adduced no evidence on this issue but the Authority’s Environmental Protection Officer, Mr Chan Kin-on, gave evidence.  He testified that he had visited the complainant’s flat above Chasers on 19 January 2002 after 2 a.m. and heard the sounds emanating from Chasers which he described:

“Strong musical bass beats ‘boom-boom’ sound and singing voices were heard.  The noise was intermittent and not in regular interval and was unpredictable.  The loudness of the bass beats and songs varied.  I could feel with my hands that the walls and floors inside the bedroom were vibrating.  I therefore considered that the primary source of noise disturbance was transmitted into the complainant’s premises through building structures and was annoying, which would interfere with sleep.  The complainant also confirmed that the noise perceived during the assessment was the type of the noise she had been complaining about.”

15.  Mr Chan recommended the “not audible” requirement and produced articles supporting such a requirement one written by Professor R.J.M. Craik, another written by Mr S. Williamson.  The Operator produced an article critical of the “not audible” requirement written by Mr Ken Dibble.  All these authors are experts in the field of acoustic measurement.  The Board rejected an argument that the night-time noise limit should be defined in decibels (dB(A)) for three reasons: the difference between the threshold of audibility and annoyance is small, annoyance is often caused by low frequency noise which may be very low in terms of dB(A) measurement and audibility is difficult to measure against background noise level.  Mr Chan did not know of any place which had adopted a decibel measurement to control the emission of music noise, especially low frequency music.  The majority of the Board formed the view that

“so long as the limit [imposed by the NAN] is conceptually certain, it could not be said that the imposition of such limit can never be justified by the terms of the Ordinance or section 13(1)(a).  At any rate, the imposition of ‘not audible’ as a condition for the licensing of certain activities is certainly done in other places, such as in Edinburgh and in the Northern Territory of Australia.  Furthermore, although ‘audibility’ as a test would necessarily import a human element, the study of Professor Craik showed that a group of people listening to music were able to agree amongst themselves the level at which the noise became audible.  Thus in reality it is unlikely that impartial persons having healthy ears would differ on the threshold of audibility.  We are thus not convinced that using ‘not audible’ as a limit would import such subjective and uncertain elements that would render the appellant to be unable to comply with the requirements of the NAN.” 

The Board, on 29 July 2002, dismissed the appeal and the Operator then sought judicial review of the Board’s decision. 

16.  The grounds on which the Operator moved for judicial review were as follows:

(1) The Board has erred in law in upholding the NAN in that the limit of “not audible” is ultra vires the Ordinance and is not prescribed by the Ordinance or the Technical Memorandum issued thereunder.

(2) The majority of the Board erred in law in its approach to the reasonableness of the NAN in imposing a limit that renders the applicant liable to criminal sanction as a result of the actions of others over which it has not control. 

17.  Chu J found that there was no error of law in the Board’s decision and dismissed the Operator’s Notice of Motion.  An appeal to the Court of Appeal succeeded.  A majority, Yuen JA and Hartmann J, allowed the appeal, Cheung JA dissented.  The Court of Appeal gave leave to appeal to this Court. 

18.  Cheung JA, affirming the decision of Chu J in the Court of First Instance, held that s.13(1) of the Ordinance was wide enough to enable the Authority to impose the “not audible” limit and that the imposition of that limit was reasonable in the circumstances.  Yuen J held the “not audible” limit to be subjective and uncertain.  Her Ladyship rejected the notion that objectivity could be given to the test by taking account of only those sounds which would be annoying to a “reasonable person”.  She said:

“Audibility is a pure test of physical sense (whether one can hear a sound).  Annoyance is a test of sensibility (whether, on hearing the sound, a reasonable person would tolerate it – see s.2 NCO).  It would be false to say that the sound is ‘not audible’ only because it was not annoying to reasonable person.”

Hartmann J was of the same view, noting that the Operator did not have unrestricted access to the noise assessment point in the flat above Chasers.  Both judges in the majority held the “not audible” requirement to be unreasonable.  The Court’s order was simply to allow the appeal.  It does not appear whether the majority held the requirement of the NAN to be ultra vires or merely unreasonable though valid. 

19.  However, the two grounds on which the Operator moved for judicial review raise distinct though related issues.  The first is solely a question of law: is the prescribing of the “not audible” requirement beyond the power of the Authority?  The second is a mixed question of fact and law: is the “not audible” requirement unreasonable in character or extent having regard to all relevant circumstances?

Ultra Vires

20.  In this Court, Mr Gerard McCoy SC who, with Ms Jennifer Ng, appeared for the Operator (the respondent) attacked the validity of the “not audible” requirement on two fronts.  He submitted that that requirement was so uncertain in content that, if the Ordinance were held to confer on the Authority the power to impose that requirement, the Ordinance would itself be invalid (at least pro tanto) for inconsistency with art.11(1) of the Bill of Rights as entrenched by art.39 of the Basic Law (“the constitutional challenge”).  The second front was based on the general law.  He submitted that s.13(2), in the context of the Ordinance and in the light of the Technical Memorandum issued pursuant to s.10(1), did not confer power to impose the inaudibility requirement.  Even if the ultra vires submissions failed, it was submitted that the Board’s decision that the requirement was reasonable was in error and should be judicially reviewed and quashed. 

21.  The constitutional challenge had not been raised in the courts below and Mr David Holgate QC who, with Mr Russell Coleman, appeared for the Authority (the appellant) objected to its being raised for the first time in this Court.  The constitutional challenge does not depend on any issue of fact, however, and it has been held in this Court that does not preclude the raising of that challenge at this stage: see Flywin Co. Ltd v. Strong & Associates Ltd (2002) 5 HKCFAR 356 at 368G-369I. 

22.  Whether it is necessary to consider the effect of the constitutional provisions on the Ordinance or the “not audible” requirement of the NAN is a question which can be put aside until the validity of the requirement is tested against the provisions of the Ordinance. 

The meaning and operation of the Ordinance and the “not audible” requirement

23.  The noise which led to the serving of the NAN was noise which answered the description set out in s.13(1)(a):

(i) it emanated from a place other than domestic premises, a public place or a construction site;

(ii) it was a source of annoyance to a person in the flat above Chasers; and

(iii) the flat above Chasers was at all material times “domestic premises” and therefore a noise sensitive receiver (NSR) as defined by the Technical Memorandum issued under s.10 of the Ordinance. 

The NAN which the Authority was thus empowered to serve on the operator of Chasers under s.13(2)(a) could therefore lawfully require the Operator “to ensure that the noise emanating from [Chasers] does not exceed [a specified] limit or standard”. 

24.  Mr McCoy SC first submitted, if I understood him correctly, that the only limit or standard which the Authority was authorized to specify was a decibel (dB(A)) limit specified by the TM.  (Indeed, the NAN did specify the decibel limits prescribed by the TM for periods other than the night-time periods).  But s.10(1) provides for the issuing of Technical Memoranda setting out “guidelines” as well as “standards and limits” and the TM that the Secretary issued directed the Authority to follow its directions “generally”: s.1 of the TM.  The TM limits are not mandatory in all circumstances.  There is nothing in the Ordinance which confines the powers of the Authority to specifying a limit or standard prescribed by the Ordinance or contained in a Technical Memorandum.  Leong J so held in Secretary for Justice v. Tak Yue Restaurant [1998] 1 HKC 236.  The argument to the contrary, which failed in both the Court of First Instance and in the Court of Appeal, must fail here.  Mr McCoy SC then submitted that the Authority was bound to have regard to the provisions of the TM and that the TM does not recommend a “not audible” limit.  Both propositions are clearly correct but they do not lead to a conclusion of invalidity. 

25.  Although the TM prescribes limits in terms of decibels, the circumstances may warrant the prescribing of a different limit.  It was not beyond the power of the Authority to impose a requirement prescribing a standard or limit that was not expressed in decibels. 

26.  Mr McCoy SC’s next argument was based on two factors.  First, that the Operator could not discover whether the sound being emitted from Chasers was audible at the assessment point in the flat above, as the Operator’s agents or servants had no right of access to that point.  Second, that audibility is dependent upon the sensitivity of a hearer and, as the sensitivity of hearers is variable, so is the concept of audibility; audibility is essentially subjective and the occasion of hearing may be transient.  That being so, the prescription of the “not audible” requirement was submitted to be so uncertain and so unreasonable as to be ultra vires. 

27.  The argument finds support in the view of the majority in the Court of Appeal.  It was in response to an argument that the definition of “annoyance” in s.2 imports the objective concept of the hearing of a “reasonable person” that Yuen JA distinguished audibility as a physical sense and annoyance as a test of sensibility. 

28.  A challenge to the validity of the “not audible” requirement on this basis evokes a reference to the principles which govern the question whether the terms of an instrument issued or served in exercise of a statutory power so as to bind another fall within the power. 

Uncertainty, Unreasonableness and Ultra Vires

29. In earlier times, the prevailing opinion was that uncertainty was a distinct criterion of invalidity of subordinate legislation, as Mathew J declared in Kruse v. Johnson [1898] 2 QB 91 at p.108:

“From the many decisions upon the subject it would seem clear that a by-law to be valid must, among other conditions, have two properties – it must be certain, that is, it must contain adequate information as to the duties of those who are to obey, and it must be reasonable.”

30. This comment, though made obiter and in a dissenting judgment (as Simon Brown LJ noted in Percy v. Hall [1997] QB 924 at p.938), was highly influential in English jurisprudence prior to Fawcett Properties Ltd v. Buckingham County Council [1961] AC 636. In that case, a local authority imposed a condition on permission to build on land in a green belt. The condition was challenged on the ground, inter alia, that it was uncertain and void. Lord Denning adopted the same approach to the validity of the condition as the courts take to the validity of a statute. He noted that there had been “a few cases where a statute had been held void because it is meaningless but none because it is uncertain” at p.676. Later in his speech, he said at p.677:

“Mr. Megarry was on stronger ground when he likened the condition to a by-law. It is a local rule laid down by a local authority and enforceable by a penalty. And he said, rightly enough, that a by-law might be held to be invalid not only because it was unreasonable but also because it was uncertain. The only case which he cited for this proposition was Scott v. Pilliner [1904] 2 K.B. 855; 20 T.L.R. 662, D.C., but when examined it turned out that the by-law there was held void, not as being uncertain, but as being unreasonable. I can well understand that a by-law will be held void for uncertainty if it can be given no meaning or no sensible or ascertainable meaning. But if the uncertainty stems only from the fact that the words of the by-law are ambiguous, it is well settled that it must, if possible, be given such a meaning as to make it reasonable and valid, rather than unreasonable and invalid.”

31. Lord Denning concluded at p.678 that:

“… a planning condition is only void for uncertainty if it can be given no meaning or no sensible or ascertainable meaning, and not merely because it is ambiguous or leads to absurd results.”

32. Diplock LJ followed Lord Denning’s approach in Mixnam’s Properties Ltd. v. Chertsey Urban District Council [1964] 1 QB 214 at p.237; affirmed though on a different point [1965] AC 735:

“The various special grounds upon which subordinate legislation has sometimes been said to be void - for example, because it is unreasonable; because it is uncertain; because it is repugnant to the general law or to some other statute - can, I think, today be properly regarded as being particular applications of the general rule that subordinate legislation, to be valid, must be shown to be within the powers conferred by the statute. Thus, the kind of unreasonableness which invalidates a by-law is not the antonym of ‘reasonableness’ in the sense of which that expression is used in the common law, but such manifest arbitrariness, injustice or partiality that a court would say: ‘Parliament never intended to give authority to make such rules’; ‘they are unreasonable and ultra vires’; Kruse v. Johnson per Lord Russell C.J. By-laws have in the past been declared void for ‘uncertainty’; see Nash v. Finlay and Attorney-General v. Denby. Some doubt is cast on the correctness of ‘uncertainty’ as a separate ground of invalidity by the speeches in the House of Lords in the recent case of Fawcett Properties Ltd. v. Buckinghamshire County Council; but if the courts can declare subordinate legislation to be invalid for ‘uncertainty’ as distinct from unenforceable, as in the case of a clause in a statute to which it is impossible to ascribe a meaning, this must be because Parliament is to be presumed not to have intended to authorise the subordinate legislation authority to make changes in the existing law which are uncertain.”

33. In Percy v. Hall [1997] QB 924, a by-law described a protected area on which trespassing was prohibited as “lands belonging to the Secretary of State in [named] parishes”. The by-law was challenged on the ground of uncertainty. The Court of Appeal adopted the Fawcett principle rather than the Kruse v. Johnson line of authority (pp 943, 950). Simon Brown LJ held the Fawcett principle to be applicable “equally to by-laws as to planning conditions, and to uncertainty of application as well as to uncertainty of language”. His Lordship commented on earlier cases in which uncertainty in application had not destroyed the validity of subordinate legislation. He said at 941:

“… At what point does a byelaw become invalid for uncertainty? It seems to me insufficient to answer, as Mr. Pleming does, that this can safely be left to the magistrates of the day or the judges on appeal. Better, surely, as with the Fawcett [1961] A.C. 636 test, to treat the instrument as valid unless so uncertain in its language as to have no ascertainable meaning, or so unclear in its effect as to be incapable of certain application in any case (often on analysis essentially the same thing: see for example Alderson v. Secretary of State for the Environment, 49 P. & C.R. 307). Being a criminal provision, it will be wherever reasonably possible construed – or, as the case may be, applied – to avoid penalty.”

He added (at p.943):

“… the Fawcett test of uncertainty should in my judgment apply to byelaws just as to planning conditions. There is no sufficient reason to distinguish between the two classes of case.”

Peter Gibson LJ was of the same view (at p.950).

34. To reject uncertainty as a stand-alone criterion of invalidity, however, did not lead Simon Brown LJ to hold that difficulty of application can never demonstrate that a purported by-law is void (at p.942):

“There may, I recognise, be cases where byelaws are enacted which quite needlessly give rise to difficulties of application. Whether these should properly be struck down for unreasonableness it is not presently necessary to decide.”

35. Diplock LJ in Mixnam’s Properties was surely correct in referring the question of validity of an impugned by-law, order or condition to the scope of the statutory power to make or impose it. If the impugned instrument falls within the scope of the power to make or impose it, it is valid; if it falls outside the scope of the power, it is invalid. This was the view of Dixon J who reviewed the history of the notions of reasonableness and uncertainty in King Gee Clothing Co Pty Ltd v. The Commonwealth (1945) 71 CLR 184 at p.195:

“… I cannot see how this history warrants the courts in adopting as a general rule of law the proposition that subordinate or delegated legislation is invalid if uncertain … I should have thought that, in this matter, they stood on the same ground as an Act of Parliament and were governed by the same rules of construction. I am unaware of any principle of law or of interpretation which places upon a power of subordinate legislation conferred upon the Governor-General by the Parliament a limitation or condition making either reasonableness or certainty indispensable to its valid exercise.”

36. Some orders have been held invalid because they were of uncertain application when the supporting power required certainty in application. This was the ground on which Dixon J held invalid a price fixing order made in purported pursuance of a wartime price fixing regulation in Cann’s Pty Ltd v. The Commonwealth (1946) 71 CLR 210 at pp 227-228:

“… What does take an order outside the power conferred by reg. 23 is, not uncertainty as to what it means, but the adoption by the order of a criterion or standard of price that is uncertain in the result that its application produces. The method of finding the maximum price must not involve discretionary elements. The order must either fix the price, or lay down a method of finding it which will produce the same result whoever applies it, so long as he uses it correctly.” (emphasis added).

37. In R v. Fenny Stratford Justices, ex parte Watney Mann (Midlands) Ltd [1976] 1 WLR 1101, a Divisional Court quashed part of a noise abatement notice which was expressed to limit the level of noise to 70 decibels because the point at which the sound level was to be assessed was not specified. That omission meant that the order was uncertain in its application and therefore void.

38. By contrast, Woolf J (as he then was) in R v. Secretary of State for Trade and Industry, ex parte Ford (1984) 4 Tr L 150, upheld the validity of an order made under the Consumer Safety Act 1978 (UK) banning the sale of scented erasers. The Act empowered the Secretary of State to make orders banning the sale of goods which the Secretary “considers are not safe and … are described in the order”. The order defined ‘scented’ to mean ‘smelling of food or flowers’. Woolf J noted that the application of the order gave rise to difficulties, and said:

“The question as to whether or not an eraser … does in fact smell of food or flowers must be very much a matter of subjective judgment … It is possible readily to envisage situations where different courts would come to different conclusions about the same eraser. That such a situation can be brought about by an order creating a criminal offence I have no hesitation in saying is highly undesirable.”

Nevertheless his Lordship observed:

“As was made clear by a series of authorities, uncertainty of language rarely creates the necessary degree of invalidity to cause the courts to intervene. It seems to me that a similar approach has to be applied to uncertainty of application, and especially in the area of consumer protection it is unfortunately inevitable that those who are responsible for supplying the public will at times be put in the situation where they will have to make difficult decisions as to whether or not they are infringing the law. They may be required to act well within the parameters of what is made lawful by the Order if they are not to run the risk of committing an offence. It would be much simpler and much more satisfactory if they could have a ready and clearly defined rule which, if complied with, would mean that they would never commit an offence. However, where one is concerned, as here, with items that are dangerous because of their aroma, I am afraid that it is impossible to exclude the element of doubt which exists with regard to the application of this Order.”

The validity of the Order was upheld.

39. In R v. Secretary of State for the Environment [2002] Env LR 510 Ouseley J dismissed an application for judicial review of a Guidance Note issued to Local Enforcing Authorities proposing that the conditions imposed on the grant of authorizations in relation to the malodorous process of animal rendering should prevent the escape of offensive odour beyond the process boundary. His Lordship rejected (at p.535) the notion that such a condition would be unenforceable because the odour would be determined subjectively by the enforcing officer rather than by an olfactometric odour measurement system, observing that the court could deal with idiosyncratic inspectors. Although the Court of Appeal dismissed an appeal from Ouseley J, the dismissal was based on the hypothesis that the Guidance Note contemplated a boundary odour condition qualified by a defence that the operator of the premises had employed the best available techniques to prevent the escape.

40. The cases show that challenges to statutory instruments on the grounds of uncertainty and irrationality depend upon the scope of the power to make the instrument, not on a judicial policy or a free-standing common law rule. Provided the impugned instrument is not so uncertain in its terms as to be meaningless, uncertainty or unreasonableness in application or inconsistency with the general law are relevant to validity only insofar as they assist in answering the question whether the instrument falls within or without the power to make it. I turn, therefore, to the statutory power to serve the NAN in this case. It was conferred by s.13(1)(a).

41. That power is conferred in order to abate the noise to which s.13(1)(a) refers, that is, a noise which is an “annoyance” to a person in the flat closest to Chasers in the Carlton Building. A requirement imposed under s.13(2)(a) that the noise should be “not audible” is clearly intended to serve the purpose of s.13(1)(a) and compliance with the requirement would have the effect of abating that noise (the “effect” rather than the “purpose” is the relevant consideration: see per Lord Diplock in McEldowney v. Forde [1971] AC 632 at p.660). There is no uncertainty of language which would preclude the use of the term “not audible” in specifying a requirement in the NAN. Is there any uncertainty in the application of the requirement?

42. The purpose of conferring the power to serve a NAN under s.13(1)(a) is to abate a noise which is a source of annoyance to an actual listener. Even though there are variations in human auditory sensitivity, the Ordinance draws no distinction between listeners of acute hearing, listeners of normal hearing and listeners of impaired hearing. True it is that the degree of annoyance which might enliven the power to serve a NAN is “annoyance that would not be tolerated by a reasonable person” but that says nothing about the auditory capacity of the “reasonable person”. It is not to the point to import the concept of “reasonableness” on the part of the listener to meet the argument that variations in acuity of hearing may produce some variation in the level of audibility of sound. Reasonable people have varying levels of auditory capacity. In any event, the purpose of serving a NAN under s.13(1)(a) is to abate the source of annoyance to a person in the particular noise sensitive receiver, whatever the person’s auditory capacity might be.

43. However, although there is some variation in human auditory capacity, the paper written by Professor Craik which Mr Chan produced to the Board shows that the subjective assessment of audibility is much more uniform and practical than assessment with a sound level meter. The paper also asserted that “during the night, when most problems occur, there is little tolerance to amplified music and so the difference between the threshold of audibility and annoyance is small”. Professor Craik dismissed objectively measurable tests of audibility as unreliable, claiming that “subjective tests give 100% correct answers”.

44. This factual background need not be relied on to establish the validity of the “not audible” requirement applicable to the night-time hours. It is at this point that the definition of “annoyance” as “annoyance that would not be tolerated by a reasonable person” becomes relevant. As a NAN served under s.13(2)(a) must have the purpose of abating the noise that constituted the annoyance which triggered the s.13(1)(a) power to serve the NAN, the requirements of the NAN must be construed as confined to abating noise which would be an annoyance to a reasonable person. So construed, the criterion of “not audible” during the night hours is entirely certain and reasonable. However, if a person is abnormally sensitive to sound, he or she must make a reasonable allowance for such sensitivity.

45. Reasonable tolerance is the concept which adjusts the protection of the listener with the freedom of the person responsible for the emission of noise. And what is reasonably tolerable depends on the circumstances. A level of noise which would be intolerable in a home for the aged or infirm might be reasonably tolerable in a factory. Tolerance is a concept which can take account of many elements. It can take account of acuity of hearing. So reasonable tolerance of noise which can be heard only by a person of unusually acute hearing must also take account of the fact that the noise would not be audible to most people. It might not be reasonable for a person with abnormal sensitivity (whether due to acuity of hearing or otherwise) to be intolerant of noise which would not be an annoyance to a person of normal sensitivity. What should be regarded as “abnormal” for this purpose depends on all the circumstances. The concept of what a reasonable person would tolerate invites attention not only to the acuity of hearing of a complainant but also to the location and character of the noise sensitive receiver and to any other relevant factor.

46. If contravention of a “not audible” requirement is to be proved by a witness, the sensitivity of the witness is a relevant consideration. Once audibility of amplified music at the assessment point during night hours is proved by a witness who is not abnormally sensitive, however, a breach is shown since a reasonable person is entitled to immunity from such a noise during the hours of sleep, especially if the music is marked by the repetitious booming of base notes. If a complainant is abnormally sensitive (whether by reason of unusual acuity of hearing or otherwise), the abnormality must be taken into account in order to determine whether, in all circumstances, it is reasonable for the complainant to be annoyed. It may or may not be reasonable for an abnormally sensitive complainant to be annoyed by a noise which he or she can hear only by reason of abnormal sensitivity.

47. Application of the “not audible” requirement does not produce a uniform quantifiable measurement but it does produce an objective standard or limit. It forbids the making of a noise which can be heard at the assessment point during the night hours. So construed, the requirement achieves a similar meaning to the meaning which the English Court of Appeal in Tod-Heatley v. Benham (1889) 40 Ch D 80 at pp 93-94, attributed to “annoyance” in a covenant as “an annoyance to reasonable people”. Once the objectivity of the “not audible” requirement appears, the objection of uncertainty fails. So construed, the requirement is clearly within the power conferred by s.13(2)(a). In the circumstances of this case, no question has arisen as to the hearing of noise which can be heard only by a person of abnormal sensitivity. No question arises as to whether the circumstances might provide a defence to a person who emits noise that can be heard only by a person of abnormal sensitivity.

48. I now return to the constitutional challenge which Mr McCoy SC supported by reference to two cases in this Court which held legal certainty to be a constitutional imperative. In Shum Kwok Sher v. HKSAR (2002) 5 HKCFAR 381 Sir Anthony Mason NPJ held that the principle of legal certainty is incorporated in art.39 of the Basic Law and in art.11(1) of the Bill of Rights but at p.410-411 he adopted what Lord Hope of Craighead had said in Sabapathee v. Mauritius [1999] 1 WLR 1836 at 1843 that the precision needed to avoid the striking down of an impugned provision “will necessarily vary according to the subject matter”. Then in Lau Wai Wo v. HKSAR [2004] 1 HKLRD 372, Lord Scott of Foscote NPJ expressed the principle of legal certainty in this way at p.388:

“The principle of legal certainty requires that a law must be sufficiently precise to enable a citizen to foresee, to a degree that is reasonable in the circumstances, the consequences that a given action may entail.”

49. The principle of legal certainty is not offended by the terms of the NAN. The person to whom the NAN is directed knows precisely what is forbidden, namely, the emission of music and other noise from Chasers which is audible in the flat above. The fact that the Operator has no right of access to the flat does not alter the precision and comprehensibility of the requirement itself. It may be difficult for the Operator to know precisely how loud the noise emanating from Chasers may be before the NAN’s requirement is breached and the Operator may need to err on the side of safety but there is no uncertainty about what constitutes a breach of the NAN’s requirements.

50. The Operator raised one further ground of challenge to the validity of the NAN’s requirements.

51. The Operator sought to derive some comfort from the fact that the level of ambient noise in Knutsford Terrace fluctuates. It was submitted that a dropping in the level of ambient noise which permitted the Chasers noise to be heard was due to the conduct of others for whose conduct the Operator is not responsible. The Operator was said to be at risk of prosecution by reason of conduct beyond the Operator’s control – a consequence that would mean that the “not audible” requirement offends a basic principle of criminal liability.

52. This submission also fails. If audible sound is emanating from Chasers in contravention of the NAN’s requirement, the persons making the ambient noise, or failing to make ambient noise, have nothing to do with the act which constitutes the contravention. The fact that ambient noise might sometimes drown out noise emitted from Chasers is immaterial. Moreover, the noise which enlivens the power to serve a NAN (and which is to be abated by a NAN’s requirements) is a noise emanating from Chasers “whether on its own or together with noise emanating from any other place”.

Judicial Review of the Boards’ decision

53. The Operator’s appeal to the Board on the ground that the “not audible” requirement was otherwise “unreasonable in character or extent” was not supported by any evidence. In the absence of contradictory evidence, Mr Chan’s evidence and the supporting papers which he produced demonstrated not only the reasonableness but the necessity of imposing a requirement of “not audible” if the residents of the Carlton Building were to be given an opportunity for undisturbed sleep.

54. The decision of the Board was reasonable. No ground for judicially reviewing the Board’s decision other than unreasonableness was advanced. The Board did not appear on the hearing of this appeal.

55. It follows that the appeal must be allowed and the Order of the Court of Appeal be set aside. In lieu thereof, the appeal to the Court of Appeal from the Court of First Instance must be dismissed with costs. The respondent must pay the costs of the appeal to this Court.

Chief Justice Li :

56. The Court unanimously allows the appeal with costs and makes the Orders referred to in the concluding paragraph of the judgment of Sir Gerard Brennan NPJ.