The following principles relevant to the present case emerge from the aforesaid discussion: (1) An arbitration clause is a collateral term of a contract as distinguished from its substantive terms; but none the less it is an integral part of it; (2) however comprehensive the terms of an arbitration clause may be, the existence of the contract is a necessary condition for its operation; it perishes with the contract; (3) the contract may be non est in the sense that it never came legally into existence or it was void ab initio; (4) though the contract was validly executed, the parties may put an end to it as if it had never existed and substitute a new contract for it solely governing their rights and liabilities thereunder; (5) in the former case, if the original contract has no legal existence, the arbitration clause also cannot operate, for along with the original contract, it is also void ; in the latter case, as the (1) I.L.R. 514 original contract is extinguished by the substituted one, the arbitration clause of the original contract perishes with it; and (6) between the two falls many categories of disputes in connection with a contract, such as the question of repudiation, frustration, breach etc.