Once arbitral proceedings have been commenced, every question concerning the proper institution of the arbitration, the existence of a valid arbitration clause and its scope must be addressed within the arbitral proceedings, with the consequence that judicial proceedings having the same subject-matter are inadmissible.
The execution of an agreement to submit disputes to contractual arbitration (arbitrato irrituale) operates as a contractual waiver of the right of action and of judicial protection, with the consequence that the commencement of judicial proceedings in the presence of a valid agreement for contractual arbitration raises a question of admissibility of the claim.