The Supreme Court on July 27, 2025, held that the doctrine of res judicata applies to successive impleadment applications filed under different provisions of the Civil Procedure Code. Where an application under Order I Rule 10 CPC is rejected on merits, a fresh application for the same relief under Section 151 CPC is barred. The ruling clarifies that res judicata operates not merely between suits but also between interlocutory applications decided on merits within the same proceedings.

Impleadment is the procedural mechanism by which a party not originally named in a suit is added as a party, either as a plaintiff or defendant. Order I Rule 10 CPC is the primary provision empowering courts to add or strike out parties, while Section 151 CPC is a residuary provision preserving the court's inherent powers to make orders necessary for ends of justice. Litigants sometimes exploit the existence of multiple CPC provisions covering overlapping ground by filing successive applications for the same relief under different provisions when one is rejected — effectively circumventing an adverse order without filing a formal appeal or review. The Supreme Court's July 2025 ruling shuts this procedural loophole. The Court held that when an impleadment application under Order I Rule 10 is rejected on merits — meaning the court examined the substance and not merely dismissed it on technical grounds — the principle of res judicata kicks in. Filing another application for the same relief under Section 151 would constitute an abuse of process. This ruling extends the classic understanding of res judicata, which traditionally applies between two suits under Section 11 CPC, into the domain of interlocutory applications within the same suit. For CLAT PG, this is critical because it tests whether candidates can distinguish between rejection on merits versus rejection on technical grounds, and understand when res judicata attaches to interlocutory orders.