Alternatively, Counsel contended that the legal position both under English and Indian Law is not as has been submitted by Counsel for Renusagar; Counsel urged both under English law and Indian law it is well settled that it is open to the parties to have an arbitration agreement incorporating words of the widest amplitude so as to embrace even the questions of its existence, validity or effect (scope) but according to him an enquiry into the scope and effect of an arbitration agreement and a challenge to the existence or validity thereof are not the same but fundamentally different inasmuch as the first pre supposes that the arbitration agreement exists in fact and in law and the enquiry then is limited to the scope and effect thereof; counsel further contended that whenever it is said that an arbitrator cannot decide the question of his own jurisdiction all that is intended is that he cannot determine that too finally, the question of the existence (factual) or validity (i.e. legal existence) of the arbitration agreement if contained in the underlying commercial Contract and this must be so, for, if the existence or validity of the underlying commercial Contract is successfully challenged the arbitration clause which is the part and parcel thereof must perish with it and therefore the Arbitrator will have no jurisdiction to decide the issue of the existence or validity of the agreement; but even here it is well settled that if the arbitration agreement so widely worded is separate and independent from the commercial Contract the arbitrator will have jurisdiction to decide the questions about the existence or validity of the commercial contract; but Counsel urged that these principles have no application whatsoever to a case where the issue relates to the scope and effect of the arbitration agreement contained in the underlying commercial contract and the arbitration agreement is wide enough to include such an issue, for, in such a case the Arbitrator will have jurisdiction to decide that issue.