It was contended that for a number of reasons these activities did not constitute a contravention of the Planning Scheme Ordinance. In the first place, it was said that the appellants had, on 30th September 1963, made what was called a development application to the respondent Council whereby they sought its approval "to conduct a high-class Private Hotel". The application described the premises as having "15 units plus Reception Hall, Cloakroom, Dining/Lounge, Lounge Annex, open Sun Verandah area, Kitchen & Staff rooms, bathrooms and toilets" and it was stated that the building had been conducted as a high-class private hotel for approximately the past twenty years. This application followed a letter of 23rd September 1963 in which the respondent advised the appellants that before the premises could be used for any purpose other than a dwelling house a development application should be submitted to the Council for consideration. In the result the respondent, on 15th October, granted its consent to the application but it was pointed out that "the premises must not, at any time, be used other than for the purpose stated above without prior consent thereto" and that, since guest house premises "are the subject of a licence under the provisions of Ordinance 42" an application should be made to the Council before putting the premises to use as proposed. On the strength of these communications the appellants assert that they had the consent of the respondent to use the premises as a guest house and that, since the use of the premises for the purpose of the so-called International Hotel Club Restaurant was merely incidental to the conduct of a guest house, they were not in breach of the Planning Scheme Ordinance. In our view, this contention must be rejected, for it is impossible to assert that the business of the International Hotel Club Restaurant was involved in or even incidental to the conduct on the premises of a guest house. Next, it was said that the use of the premises for the conduct of the activities involved in the International Hotel Club Restaurant was merely, in the words of cl. 31 of the Planning Scheme Ordinance, the practice by the appellants, as occupants of a residential building, "of a profession or occupation" which did not involve the use of the residential building for the purpose of an industry; it was said that the first-named appellant's occupation was that of caterer and he was doing no more than "practising" his "occupation" as an occupant of a residential building. In our view this contention should also be rejected. What is contemplated as the use of a residential building is that it will have a number of occupants and the contention may be more simply tested by considering the simple case of an occupant of a dwelling house situated in a living area. The effect of cll. 26 and 28, together with the Table which is appended to the former clause, is that it may be used only as a dwelling house without consent. But it may not be used without consent for any of the purposes specified in Column IV of the Table which include such things as "Shops", "Commercial Premises" or any other purpose not referred to in Column III or Column V. Nor, even with consent, may it be used for any of the purposes specified in Column V. It is in the light of these specific and exclusive prohibitions that it is necessary to consider the scope of the exceptions created by cl. 31. It seems to us that the relevant words of cl. 31 should not be so widely construed as to enable the occupant of a dwelling house, or for that matter an occupant of a residential building, to carry on upon the premises any sort of trade or business in any manner he chooses so long as it does not involve the use of the premises for the purpose of an industry. If it were so construed it would mean of course, the premises could be used, for example, as a shop or as commercial premises or professional chambers notwithstanding that such a use without consent is explicitly prohibited by cl. 28. What the exception permits, it seems to us, is the use of the premises by an occupant for the "practice" of some personal skill which is a qualification of his profession or occupation. Moreover, the practice must be ancillary only to the occupation of the occupant in question and, therefore, a use which does not operate to transform the character of the dwelling house. In other words, the "practice" must be ancillary to his occupation of the dwelling house as such and the exception has no application to a case where a business is conducted in a dwelling house and the occupancy is merely incidental to the conduct of the business (cf. the situation which arose in Harnam Singh v. Jamal Pirbhai [1] ). It is difficult to frame a more precise test and in some cases there may be difficulties in drawing the line, but there is no difficulty in the present case for the trade which the appellants conducted cannot, in any way, be regarded as the "practice" of an occupation which is ancillary to an occupation of the premises as a residential building of the type for which they received approval. It is true, of course, that the first-named appellant was one of the occupants of a residential building of the type for which he had received approval but it is impossible to regard the substantial business which was conducted as the practice of his "occupation" incidentally to his situation as an occupant of the residential building. We appreciate that this may be thought to place a somewhat more limited meaning on cl. 31 than the Supreme Court was prepared to adopt in Ku-ring-gai Municipal Council v. Cooney [2] but we do not suggest that a practice must be carried on pursuant to the clause without the assistance of others. The point which we wish to make is that it is essential that, notwithstanding the "practice", the premises should continue to be used essentially as a dwelling house or, in this case, as a residential building, and this condition is not satisfied where the premises are primarily used as business premises and the owner's occupancy is merely incidental to the conduct of the business.