4 Substantive Equitable Set-Off

4.01 There is a substantive1 form of equitable set-off which is not confined to mutual debts,2 and which has attracted considerable attention in recent years. It is the most elusive, but at the same time the most important, of the various forms of equitable set-off. 4.02 The seminal authority on this form of equitable set-off is Lord Cottenham's judgment in Rawson v Samuel.3 The Lord Chancellor said that the mere existence of cross-demands is not sufficient to give rise to a set-off. Rather, he said that the applicant for relief must show some good equitable...