CA 20 May 1987. Appeal by building owners (B) against decision dismissing their originating summons and granting declarations sought by contractors (C) concerning the contract for the construction of six warehouse units under the JCT 1963 Form (Private Edition, Without Quantities) (1977 Revision). When a dispute arose C claimed arbitration under Cl.35(1), seeking rectification of the contract on the ground that it was entered into as a result of either a mutual or unilateral mistake and damages for innocent misrepresentation or negligent mis-statement. B contended that the arbitrator had no power under the clause to order rectification of the contract, nor did he have the power to grant relief for misrepresentation , and issued an originating summons seeking declarations to that effect. C issued a corresponding originating summons for declarations that the arbitrator did have jurisdiction. The previous court dismissed B`s summons and granted C the declarations sought. CA agreed with