Court case(1410) YB 11 Hen IV, fo 47, pl 21

The plaintiffs were the masters of the grammar school at Gloucester, an old-established school which, they claimed, had long enjoyed the exclusive right of teaching boys in the town. The defendant, a schoolmaster, set up a rival school in the same town. To attract pupils he charged lower fees: the plaintiffs had been charging forty pence a quarter for each pupil, and the competition compelled them to reduce their fee to twelve pence. Many pupils left the plaintiffs' school for the defendant's. The plaintiffs sued the defendant for the loss of income caused to them by his competition.

The court held that the action did not lie. Setting up a school and teaching boys is a lawful and good act, and competition in it, though it causes loss to an existing teacher, violates no legal right of his. Hankford J observed that damage may be done without injury (damnum absque injuria): if a man has a mill and another builds a mill next to it, so that the first loses his customers, the first has no action, because the second has done nothing unlawful. The plaintiffs had suffered real loss, but since no legal right of theirs had been infringed, they had no remedy.