Currie v Misa (1875) LR 10 Ex 153. Lush J''s definition of consideration: ''some right, interest, profit, or benefit accruing to the one party, or some forbearance, detriment, loss, or responsibility, given, suffered, or undertaken by the other''. The standard formulation, repeated in every modern textbook.
Stilk v Myrick (1809) 2 Camp 317. Sailors deserted mid-voyage; the master promised the remaining crew the deserters'' wages if they would work the ship home. Lord Ellenborough held that the promise was unsupported by consideration: the remaining crew were already obliged by their original contracts to do whatever was necessary to get the ship home. The case is the foundational authority on the existing-duty rule.
Pinnel''s Case (1602) 5 Co Rep 117a. ''Payment of a lesser sum on the day in satisfaction of a greater cannot be any satisfaction for the whole.'' The rule that part-payment of a debt does not discharge the debt — even where the creditor expressly agrees. The exceptions — payment of a different thing, at a different time or place, or by deed — are recognised in the same case.
Foakes v Beer (1884) 9 App Cas 605. The House of Lords applied Pinnel''s rule to a written agreement that the creditor would accept instalment payments in full satisfaction of a judgment debt. Despite the Earl of Selborne LC''s acknowledgement that the rule was open to criticism, the court declined to depart from it. The case fixed the rule for the next century.
Hughes v Metropolitan Railway (1877) 2 App Cas 439. A landlord had served a notice to repair on the tenant; negotiations followed and the tenant did not repair within the statutory period. The House of Lords held that the negotiations operated to suspend the running of the period — a precursor of promissory estoppel articulated by Lord Cairns LC. The case provided the doctrinal foundation that Denning J built on in High Trees.
Central London Property Trust v High Trees House [1947] KB 130. The landlord had agreed during the war to accept reduced rent because of the difficulty of finding tenants in central London during bombing. After the war, when occupancy improved, the landlord''s receivers sued for the full rent. Denning J held that the landlord could recover the full rent for the post-war period (the war-time concession was understood as conditional on the war-time difficulties) but suggested that, had the landlord sought to recover the unpaid rent for the war years, the claim would have been defeated by an estoppel. The case is the foundational modern authority on promissory estoppel.
Combe v Combe [1951] 2 KB 215. The Court of Appeal held that promissory estoppel could not be used as a sword (a cause of action) — it operates only as a shield (a defence). Mrs Combe, relying on her ex-husband''s promise of maintenance, sued for breach of that promise; the absence of consideration meant there was no contract, and estoppel could not supply the missing element. Denning LJ acknowledged the limits of his own High Trees doctrine.
Williams v Roffey Bros & Nicholls (Contractors) Ltd [1991] 1 QB 1. The Court of Appeal held that performance of an existing contractual duty can be consideration for a promise of additional payment if the promisor obtains a practical benefit (or avoids a practical disbenefit) from the performance. Glidewell LJ at 16 articulated the test: (i) A has a contract with B for goods or services; (ii) at some stage B has reason to doubt whether A will be able or willing to perform; (iii) B promises A additional payment in return for A''s promise to perform the existing obligation; (iv) as a result of giving the promise B obtains a practical benefit; (v) B''s promise is not given as a result of economic duress or fraud; then (vi) the benefit is consideration. The decision is the most significant modern reformulation of the existing-duty rule.
Re Selectmove Ltd [1995] 1 WLR 474. The Court of Appeal held that the Williams v Roffey practical-benefit doctrine did not extend to part-payment of a debt; Foakes v Beer governed. The decision preserved the asymmetry: variation by additional payment may be supported by practical benefit; variation by acceptance of less is not.
MWB Business Exchange Centres Ltd v Rock Advertising Ltd [2018] UKSC 24. The Supreme Court considered (in obiter) whether Foakes v Beer should be overruled. Lord Sumption JSC at [18] noted the doctrine''s ''embarrassments'' but the court ultimately decided the case on the no-oral-modification clause, leaving Foakes v Beer untouched. The case shows the continuing tension between the Williams v Roffey logic and the Pinnel''s rule on part-payment of debt.
D & C Builders v Rees [1966] 2 QB 617. The Court of Appeal held that promissory estoppel was unavailable to a debtor who had used economic pressure (knowing the creditor''s financial difficulties) to induce the creditor to accept part-payment in settlement. Lord Denning MR introduced the ''clean hands'' qualification: estoppel is an equitable doctrine and equity will not assist a party who has used unconscionable pressure.