In a ruling dated 12 March 2026 (case ref. III CZ 18/26), arising from proceedings concerning the acquisition of real property by adverse possession, the Supreme Court reiterated that anyone seeking a swift conclusion to such proceedings should take particular care to identify all persons with an interest in the outcome. Overlooking, for example, the heir of a former participant in non-contentious proceedings and proceeding to judgment may result in that judgment being set aside and the case remitted for reconsideration — as indeed occurred in the case under discussion.

Who participates in non-contentious proceedings, and from when?

Pursuant to Article 510 § 1 of the Code of Civil Procedure, any person whose rights are affected by the outcome of non-contentious proceedings is considered an interested party. Such a person may join the proceedings at any stage, up to the conclusion of second-instance proceedings. Upon doing so, they acquire the status of a participant. The provision sets no fixed deadline for summoning an interested party — this may occur at any point prior to the close of the appellate proceedings. However, as illustrated by the ruling under discussion, the Supreme Court noted that the later the summons, the more serious the procedural consequences.

As the Supreme Court observed in this ruling, a court should promptly summon an interested party to participate in the proceedings if, from the content of the application or the circumstances invoked, it is apparent that a person with an interest in the outcome is not already participating as a party.

Summoning a participant only at the appellate stage does not render the first-instance proceedings invalid; however, it does give rise to an effective objection based on the deprivation of the right to appeal against the decision — which may result in the ruling being set aside and the case remitted for reconsideration. In adverse possession proceedings, the circle of interested parties is broad: it encompasses not only owners and their heirs, but also dependent possessors, lessees, users, and persons entitled under limited rights in rem.

The Supreme Court confirmed the well-established judicial view that the category of interested parties in adverse possession proceedings is broader than one might intuitively suppose. Participants should include not only the current owners of the property or their heirs, independent possessors other than the applicant, possessors of neighbouring land claiming rights to the property or to boundary strips of land, and persons holding limited rights in rem over the property, but also dependent possessors — that is, lessees, users, and persons exercising control over the property on any other legal basis.

The condition for participation is demonstrating that the outcome of the proceedings will affect the rights of the person concerned. Not everyone who has any connection to the property will automatically become a participant — but everyone with a genuine legal interest in the outcome should be summoned to the proceedings.

May a party who joins the proceedings at a later stage seek the repetition of evidence?

In the context of this ruling, the Supreme Court drew attention to a practically significant scenario: what happens when an interested party is summoned to participate after part of the evidentiary proceedings have already been conducted, but before the close of the hearing at first instance? In such circumstances, the Supreme Court emphasised that the participant may submit applications for the taking of evidence, including an application for the repetition of evidence already heard. However, they must put forward persuasive grounds justifying the need for evidence to be taken again, specifically linked to the fact that they did not participate in the earlier evidentiary proceedings. This is therefore not an unconditional right — the participant must demonstrate that their absence at the earlier stage genuinely warrants the repetition of evidentiary steps. Nonetheless, it represents a real risk of further prolonging proceedings that are already protracted.

Correctly identifying the participants is the foundation of efficient resolution of an application

The practical conclusion is unequivocal: at the very stage of lodging the application, the applicant should ensure that all persons with an interest in the outcome are correctly identified. Overlooking even one of them may lead to proceedings being prolonged for years — and for reasons that are entirely procedural, wholly unconnected to the substantive merits of the claim.

The participants in the proceedings under discussion experienced this first-hand. The Supreme Court found that, since not all persons whose participation was required had taken part in the proceedings before the district court, the first-instance court had not addressed the substantive basis of the application within a properly constituted arrangement of parties. That alone was sufficient to justify remitting the case for reconsideration — even though the Supreme Court noted in passing that the issue of supplementing the evidential material (raised in the grounds of appeal) did not in itself warrant setting aside the judgment, as the appellate court could have supplemented the evidence of its own motion.