“47. Whatever its strict meaning may be, the maxim in its less literal sense can be appealed to in the present context as an expression of legal policy. It is well settled in cases where a wrongful act has caused personal injury there is no cause of action if the damage suffered was negligible. In strict legal theory a wrong has been done whenever a breach of the duty of care results in a demonstrable injury, however slight. But the policy of the law is not to entertain a claim for damages where the physical effects of the injury are no more than negligible. Otherwise, the smallest cut, or the lightest bruise, might give rise to litigation the costs of which were out of all proportion to what was in issue. The policy does not provide clear guidance as to where the line is to be drawn between effects which are and are not negligible. But it can at least be said that an injury which is without any symptoms at all because it cannot be seen or felt and which will not lead to some other event that is harmful has no consequences that will attract an award of damages. Damages are given for injuries that cause harm, not for injuries that are harmless. … 49. This approach does not seem to me, however, to address the fundamental point that, while the pleural plaques can be said to amount to an injury or a disease, neither the injury nor the disease was in itself harmful. This is not a case where a claim of low value requires the support of other claimants to make it actionable. It is a claim which has no value at all. Pleural plaques are a form of injury. But they are not harmful. They do not give rise to any symptoms, nor do they lead to anything else which constitutes damage. Furthermore it is not possible to bring the risks of developing a harmful disease into account by applying the ordinary rules of causation. The risks are no doubt due to the same exposure to asbestos. But they are not created, or in any way attributable to, by the pleural plaques. That can also be said of anxiety. It is the risk of developing a harmful disease in the future that gives rise to it. So also where the claimant is required to attend for the periodical medical attention and is worried about the results. Pleural plaques themselves do not require periodical medical attention. The need for this is due to what the pleural plaques indicate about the extent of exposure to asbestos.”
“How is the scope of the duty determined? In the case of a statutory duty, the question is answered by deducing the purpose of the duty from the language and context of the statute: Gorris v Scott (1874) L.R 9 Ex. 125. In the case of tort, it will similarly depend upon the purpose of the rule imposing the duty. Most of the judgments in the Caparo case are occupied in examining theCompanies Act 1985 to ascertain the purpose of the auditor’s duty to take care that the statutory accounts comply with the Act. In the case of an implied contractual duty, the nature and extent of the liability is defined by the term which the law implies. As in the case of any implied term, the process is one of construction of the agreement as a whole in its commercial setting. The contractual duty to provide a valuation and the known purpose of that valuation compel the conclusion that the contract includes a duty of care. The scope of the duty, in the sense of the consequences for which the valuer is responsible, is that which the law regards as best giving effect to the express obligations assumed by the valuer: neither cutting them down so that the lender obtains less than he was reasonably entitled to expect, nor extending them so as to impose on the valuer a liability greater than he could reasonably have thought he was undertaking.”