In The Procter & Gamble Co v Svenska Cellulosa Aktiebolaget SCA,3 a claim for rectification was resisted on the basis of an entire agreement clause. Following a number of earlier first instance decisions,4 Hildyard J concluded that the clause would exclude a collateral warranty but was no bar to rectification. The judge referred to established authority5 showing rectification’s underlying nature as a tool for reforming an instrument intended as a record of a bargain and not for varying, modifying or extending the bargain itself. Rectification brings out the true common accord, and an entire agreement clause guards the four corners of that accord from “side, collateral or additional agreement qualifying or adding to” it.6 The difficulty is in determining whether the relief is sought to correct a mistake in expressing the accord which remains “the sole source of obligations between the parties” or to give effect to a different “compact or understanding not intended to be expressed by words the parties have used”.7