The great majority of claims which are made in the civil courts are for damages to compensate for a loss which has occurred. Compensation will be awarded on the principle of restoring the person who has suffered a loss through the wrong of another to the position they would have been in if the wrong not happened.
One of the basic principles of UK law is that a person may not benefit financially but only be compensated for the actual lots. A claimant is only entitled to damages to compensate them for the loss that they can show has been incurred. Should a car crash in to my garden wall I will only be entitled to the cost of repairing the wall to its original condition. I cannot claim for the cost of building a new wall over and above the specification of the old.
There is however another type of claim where the loss suffered is not immediately apparent. Were I to instruct a firm of solicitors to act for me in bringing a claim over a traffic accident where I was hurt. They negligently miss the limitation period for bringing the claim, as a result of which I lost the chance of recovering damages from the driver of the car which hit me. The amount of damages which I can claim from the negligent solicitor will be based on the amount I would have received had it not been for their negligence. My Claim can only be for the amount I would have received in my accident claim had I been able to proceed with it.
The claim being brought against the negligence solicitor will be for the loss of chance. That is the loss of the chance to recover damages from the driver of the car. It will first therefore be necessary to calculate how much I would have been likely to recover from my accident claim.