The institution of collateral intervention

The legislature states in Article 76 of the Code of Civil Procedure that “Any person who has a legal interest in the case being decided in favour of one of the parties may, at any stage of the proceedings up to the conclusion of the hearing in the second instance, join that party”. Usually, the intervener – that is, a natural or legal person intervening in the proceedings – is first summoned to participate in the case by way of a joinder.

A third-party intervention is drawn up in the form of a procedural document, for which, in principle, no specific restrictions are laid down. The document must state the intention to join the case and specify which party one is joining. It is also mandatory to demonstrate one’s legal interest, i.e. to describe why it is in one’s interest for a particular party to win the case. It should also be emphasised that a legal interest will only exist if the judgment to be delivered affects the intervener directly or indirectly. The submission must be paid for in accordance with the requirements of the Act on Court Costs in Civil Matters. Article 130 of the Code of Civil Procedure, concerning the return of procedural documents, will apply to any submission that does not meet the formal requirements. It is also worth noting that, alongside the act of intervening in the case, the intervener may also perform another procedural act.

Incidental intervention undoubtedly serves to safeguard the interests of the party joining the proceedings. This is the case, for example, where the debtor does not consent to a change in the party acting as the claimant. It should be recalled that in court proceedings, a purchaser may only step into the shoes of the seller with the consent of the opposing party. A lack of consent from the debtor would mean that the new creditor would be deprived of the opportunity to pursue their claims. However, thanks to the institution of incidental intervention, we can join the proceedings without the consent of our hypothetical debtor and expect a favourable outcome of the case.