The possibility for an
arbitral tribunal to pronounce or declare set-off as a means of rejecting
wholly or partially a claim is a particularly complex question, which reveals
the ambiguity of the set-off mechanism. Whilst the arbitrator’s jurisdiction is
not in doubt where the claim which forms the basis for set-off originates from
the same legal relationship as that in relation to which he is seized — subject
to specific problems resulting from the commencement of insolvency proceedings against
the debtor — this is not the case where the alleged claim arises out of a
distinct legal relationship, over which the arbitrator lacks jurisdiction on a
principal basis. In such a situation, the arbitrator will only have
jurisdiction in exceptional cases.