Prosecution History Estoppel And Trade Mark Infringement: Recent Developments

Recently, the doctrine of prosecution history estoppel, which finds its roots in patent infringement proceedings, has been seeing frequent application in trade mark infringement proceedings as well. While estoppel does not find reference in the trade mark statute, the Indian Evidence Act, 1872 defines estoppel as "when one person has, by his declaration, act or omission, intentionally caused or permitted another person to believe a thing to be true and to act upon such belief, neither he nor his representative shall be allowed, in any suit or proceeding between himself and such person or his representative, to deny the truth of that thing"¹. This doctrine, which often serves as a strong arrow in a litigant's quiver of arguments, is based on the premise that parties cannot take a stance which is completely contrary to their submissions as regards the same trade marks made in earlier proceedings. As such, an understanding of the numerous ways in which courts have