" …Mr Lagden's claim was, in essence, a claim for the loss of use of his car while it was in the garage undergoing the repairs which needed to be done as a result of the accident. There was no evidence that he would have suffered financial loss as a result of being unable to use his car during this period. But inconvenience is another form of loss for which, in principle, damages are recoverable. So it was open to him, as it is to any other motorist, to avoid or mitigate that loss by hiring another vehicle while his own car was unavailable to him. The expense of doing so will then become the measure of the loss which he has sustained under this head of his claim. It will be substituted for his claim for loss of use by way of general damages. But the principle is that he must take reasonable steps to mitigate his loss. The injured party cannot claim reimbursement for expenditure by way of mitigation that is unreasonable. "
" ...In my judgment, the following principles apply to claims for financial losses suffered by self-employed drivers when their vehicles are off the road pending repair or replacement: 16.1 The starting point is that the professional driver's vehicle is a profit-earning chattel and that the true loss is the loss of profit suffered while the damaged vehicle is reasonably off the road pending its repair or replacement: Commissioners for Executing the Office of Lord High Admiral of the United Kingdom v. Owners of the Steamship Valeria [1922] 2 A.C. 242 ; Clerk & Lindsell on Torts (22 nd Ed), para. 28-121. 16.2 Of course, a claimant might choose instead to hire a replacement vehicle in order to be able to continue trading. Properly analysed, this is a claim for expenditure incurred in mitigation of the primary loss: Lagden v. O'Connor, at [27]; Umerji v. Khan[2014] EWCA Civ 357 , [2014] R.T.R. 23, at [37] . Like any other expense incurred in a reasonable attempt to mitigate a claimant's loss, such hire costs are prima facie recoverable. Where, for example, the claimant successfully mitigates his or her loss by hiring a replacement vehicle at a cost lower than the hypothetical loss of profit, the court will award the lower hire charges. 16.3 A claimant cannot recover any additional loss suffered by reason of a failure to take reasonable steps to mitigate his or her loss: British Westinghouse Electric & Manufacturing Co. Ltd v. Underground Electric Railways Co. of London Ltd[1912] AC 673 , at 689; Dunkirk Colliery Co. v. Lever(1878) 9 Ch D 20 , at page 25. 16.4 Claimants cannot, however, be expected to weigh precisely their losses. In Banco de Portugal v. Waterlow & Sons Ltd[1932] AC 452 , Lord Macmillan observed at page 506: "