Contractual arbitration (arbitrato irrituale) is incompatible with the public character of a contracting party, inasmuch as it entails the delegation to third parties of the formation of the contractual will of the public administration, without the guarantees of transparency, publicity and supervisory control required for the pursuit of the public interest.
The nullity of an arbitration clause providing for contractual arbitration (arbitrato irrituale) stipulated by the public administration entails the nullity of the arbitral award rendered by the arbitral tribunal on the ground of defect of potestas iudicandi (absence of arbitral jurisdiction).
The radical nullity of an arbitral award on the ground of defect of potestas iudicandi is susceptible of being raised ex officio by the court even in proceedings for challenge of the award, independently of any prior submission during the arbitral proceedings.