The Historical Roots of Patent Injunctions: Revisiting Horton v. Maltby (1783)

by Dennis Crouch

In the ongoing debate over the proper standard for issuing injunctions in patent cases, a 240-year-old English Chancery decision has taken on renewed significance. Horton v. Maltby, LI Misc MS 112 (Ch. 1783), provides a window into the traditional principles of equity that modern U.S. courts are instructed to apply when considering injunctive relief for patent infringement.

The case arose when Horton, who had obtained a patent for a stocking-making machine, filed a bill in Chancery (England's primary court of equity until 1875) against Maltby for allegedly infringing the patent. Horton sought three equitable remedies: accounting of profits, delivery or destruction of the infringing machines, and an injunction to prevent further use. Maltby requested immediate dismissal via demurrer, arguing that Horton should first establish his right at law before seeking equitable relief.

Lord Ashurst, wrote the primary opinion rejecting the demurrer. His opinion draws a parallel between patent and copyright cases, noting that in both instances, ongoing infringement during litigation could cause "irreparable injury" to the rights holder. The opinion's reasoning suggests that the mere fact of continued infringement during the litigation was sufficient to establish irreparable harm—a key factor in granting injunctive relief.