In the UK, Lord Leggatt describes the "function of the doctrine of mitigation" as enabling the law to distinguish between effects on the claimant's financial position which are to be regarded as caused by the defendant's breach of contract and for which damages can therefore be recovered and effects which are attributed to the claimant's own action or inaction in response to the breach and for which the defendant is not liable.
[4] The issue of what is reasonable is especially contentious in personal injury cases where the plaintiff refuses medical advice.
[6] The actions of the defendant may also result in the mitigation of damages which would otherwise have been due to the successful plaintiff.
In Manton Hire & Sales Ltd v Ash Manor Cheese Co Ltd. (appeal judgment in 2013), the hirer of an unsuitably wide fork lift truck was justified in rejecting the supplier's proposed mitigation when the supplier had "only [made] an unclear offer to modify the product without specifying "the exact extent" to which the truck was to be modified.
[7] In the case of Thai Airways International Public Company Ltd v KI Holdings Co Ltd. (2015), a number of mitigating actions are listed which had been taken by Thai Airlines in response to a supplier's failure to deliver airplane seating which had been ordered for its planes.