Contractual arbitration (arbitrato irrituale) has a contractual nature, in that the parties entrust the arbitrators with the task of settling the dispute by means of an ascertainment agreement, undertaking to consider the decision as an expression of their own will; the content of such agreement is not limited to the attributions set out in the operative part, but includes also the ascertainment of the parties’ rights and obligations, which constitutes its logical-legal basis.
The judicial declaration of nullity of a contractual arbitral award (lodo irrituale), once final, deprives the claim founded on the award of its contractual basis, with consequent automatic lapse of the payment order obtained on the basis of the arbitral decision, as it is irremediably devoid of justifying cause.
The submission of a dispute to arbitrators precludes the party from asserting in judicial proceedings the right to payment on a basis other than the contractual one constituted by the arbitrators’ decision, so that, once the award is set aside, it is not permitted to modify the cause of action of the claim for payment originally founded on the arbitral award.
Where the same party has brought both opposition proceedings to a payment order founded on a contractual arbitral award (lodo irrituale) and a challenge to the award itself, the opposition grounds are not inadmissible for lis pendens, but rather the opposition proceedings must be stayed pursuant to Article 337, paragraph 2, of the Code of Civil Procedure, by reason of the relationship of prejudiciality-dependence with respect to the ascertainment of the logical-legal basis of the claim.