Held, appeal allowed. On its natural and proper construction the exclusion of entitlement to compensation in article 9(4)(c) of the tree preservation order had no temporal restriction on the consideration of whether or not the loss or damage was reasonably foreseeable by the person in question and attributable to his failure to take reasonable steps to avert it or mitigate its extent. A tribunal was not required to confine its attention to a specific date, which might lead to an overly restrictive consideration of the questions of reasonable foreseeability and reasonable steps. It was free to consider those questions within the relevant span of time—bearing in mind always that the relevant “loss or damage” it was considering was the “loss or damage” flowing from the refusal of consent or the granting of consent subject to conditions. It was neither appropriate nor indeed possible to prescribe, for all cases, what the relevant span of time would be. It would depend on the particular circumstances of the case in hand, and would be, in every case, for the tribunal, directing itself properly, to resolve as a matter of fact and judgment. In the present case the tribunal had erroneously restricted its consideration of the matters in 9(4)(c) solely to the position as it had been when the conservatory was built when it ought to have considered the questions of reasonable foreseeability and reasonable steps having regard to the whole period between the construction of the conservatory and the relevant “loss or damage” being “caused or incurred”. Further, the tribunal’s reasoning did not show that the specific questions arising had been properly grappled with (paras 37–38, 39–41, 46, 47).

Per curiam. (i) It would be impossible to lay down any general rule about the circumstances in which a tribunal may justly conclude that it would not be right to attribute to a claimant the reasonable foresight of his contractor or “specialist agents”. A claimant will not always be able to avoid the conclusion that the relevant loss or damage was reasonably foreseeable by him, though not actually foreseen, in spite of there being no direct evidence on the question either from the claimant himself or from the contractor who did the work for him—or for a predecessor in title. In some cases it will be quite obvious from the outset that the contractor has undertaken the work incompetently or without proper care, and that this either was or should have been apparent to the claimant himself straight away. In others, the shortcomings in the contractor’s work may go unnoticed until after the loss or damage has occurred. And in others again, such defects may emerge only some time after the work was done, but before the loss or damage occurs. Inadequate foundations for a building may be a good example. In cases falling within the second and third categories, the tribunal may or may not be able to find that the loss or damage was reasonably foreseeable by the claimant. But a finding that it was not reasonably foreseeable by him in such circumstances, simply because the work in question was done not by the claimant himself but by a contractor, is not inevitable or automatic (paras 47, 48).

(ii) The statutory scheme and the provisions of article 9 of the order do not, in principle, prevent an award of compensation being made to a claimant who may also have a claim in negligence against a contractor responsible for the defective construction of a building, such as by constructing it on inadequate foundations. However, the fact that the building that has sustained loss or damage was erected before the making and confirmation of the tree preservation order does not, in principle, prevent the tribunal from finding that the claimant has, nevertheless, failed to discharge the duty to mitigate his loss under article 9(4)(c). Neither of those two observations should be regarded as incompatible with any corresponding principles in the law of nuisance (para 58).