Damages are the pecuniary recompense given by process of law to a person for the actionable wrong that another has done him. Damages may, on occasion, be awarded where the plaintiff has suffered no ascertainable damage: damage may be presumed.
Day v Brownrigg (1878) 10 ChD 294 at 304, CA, per Jessel M.R.:
You must have in our law injury as well as damage. The act of the defendant, if lawful, may still cause a great deal of damage to the plaintiff. If a man erects a wall on his own property and thereby destroys the view from the house of the plaintiff, he may damage him to an enormous extent. He may destroy three fourths of the value of the house; but still, if he has the right to erect the wall, the mere fact of thereby causing damage to the plaintiff does not give the plaintiff a right of action.