An arbitration clause inserted in a public procurement contract without having been previously indicated in the call for tenders or without the required authorisation is void pursuant to Article 209(1) and (2) of Legislative Decree No. 50/2016, as amended by Legislative Decree No. 56/2017, with the consequent inadmissibility of the arbitration claim and the establishment of the jurisdiction of the ordinary court, which has jurisdiction to hear claims for damages originally submitted to the arbitrators by virtue of the arbitration clause that has become ineffective.