The United Kingdom Supreme Court handed down judgment on 11 April 2017 in the case of Lowick Rose LLP v Swynson Ltd  UKSC 32.
The case is interesting for a number of reasons, but for present purposes I want to draw attention to paragraph 11 of Lord Sumption’s speech (for the majority), in which he summarized the legal principle known as ‘Res Inter Alios Acta’:
“The general rule is that loss which has been avoided is not recoverable as damages, although expense reasonably incurred in avoiding it may be recoverable as costs of mitigation. To this there is an exception for collateral payments (res inter alios acta), which the law treats as not making good the claimant’s loss. It is difficult to identify a single principle underlying every case. In spite of what the latin tag might lead one to expect, the critical factor is not the source of the benefit in a third party but its character. Broadly speaking, collateral benefits are those whose receipt arose independently of the circumstances giving rise to the loss. Thus a gift received by the claimant, even if occasioned by his loss, is regarded as independent of the loss because its gratuitous character means that there is no causal relationship between them. The same is true of a benefit received by right from a third party in respect of the loss, but for which the claimant has given a consideration independent of the legal relationship with the defendant from which the loss arose. Classic cases include loss payments under an indemnity insurance: Bradburn v Great Western Railway Co (1874-5) LR 10 Ex 1. Or disability pensions under a contributory scheme: Parry v Cleaver  AC 1. In cases such as these, as between the claimant and the wrongdoer, the law treats the receipt of the benefit as tantamount to the claimant making good the loss from his own resources, because they are attributable to his premiums, his contributions or his work. The position may be different if the benefits are not collateral because they are derived from a contract (say, an insurance policy) made for the benefit of the wrongdoer: Arab Bank Plc v John D Wood Commercial Ltd  1 WLR 857 (CA), at paras 92-93 (Mance LJ). Or because the benefit is derived from steps taken by the Claimant in consequence of the breach, which mitigated his loss: British Westinghouse Electric and Manufacturing Co Ltd v Underground Electric Railways Ltd  AC 673, 689, 691 (Viscount Haldane LC). These principles represent a coherent approach to avoided loss. In Parry v Cleaver, at p 13, Lord Reid derived them from considerations of “justice, reasonableness and public policy”. Justice, reasonableness and public policy are, however, the basis on which the law has arrived at the relevant principles. They are not a licence for discarding those principles and deciding each case on what may be regarded as its broader commercial merits.”
The doctrine of ‘Res Inter Alios Acta’ is a part of Bermuda common law, following English common law, having been cited and applied in at least 2 reported Bermuda cases over the years…