(iv)  Conclusion on promissory estoppel in the Common law

The existence of an equitable doctrine of promissory estoppel, though helpful in providing a way of enforcing renunciations of contractual rights, also causes problems of seemingly inconsistent results in law. If one compares the results in two cases mentioned earlier, Foakes v. Beer and Central London Property Trust v. High Trees House, it is very hard to see why opposite outcomes should have been reached merely because one claim was at law and one in equity. In Foakes, the common law posi­ tion was applied that a creditor is not bound by a bare promise to accept less than the full debt owed by the debtor. This meant that Mrs Beer, who had assured her debtor that she would consider the debt satisfied if the principal amount was paid off over time in instalments, was not precluded from subsequently claiming interest in addition to this sum. By contrast, in High Trees, the landlord who had assured his tenant that the ground rent would be varied below that stated in the contract of lease, was precluded from going against this promise on account of the equitable defence pled by the debtor. Common law and equity seem to pull in different directions, in a way which is hard to justify. A better result would surely be reached if it were accepted that promises either to renounce or forego rights ought generally to be enforceable at law, however the claim is framed, and whether or not consideration has been given for the promise.

(b)  Mixed legal systems

(i)  South Africa

Because South Africa does not recognise a doctrine of promissory estop­ pel, clearly such a doctrine cannot support an argument that rights have been renounced as a result of the behaviour of a party incompatible with such rights. South African law, like English law, does, however, have a doctrine of estoppel by misrepresentation, though such a doctrine is evi­ dently of limited use in explaining circumstances which could be char­ acterised as a renunciation of rights by conduct, given that estoppel by misrepresentation relates to statements of present fact rather than of future conduct.

Renunciations of rights in South Africa are thus accommodated with ease only within an express, contractual setting (no consideration being required for the renunciation), though it should be noted that such

contractual waiver (discussed earlier) may be undertaken impliedly, so long as there is clear evidence for such implied waiver.56 There is thus some scope for accommodating conduct-based renunciations of rights in South African law, albeit that the conduct must indicate contractual intent.

(ii)  Louisiana

There ought to be, and indeed there is, much less need for a doctrine of promissory estoppel in Louisiana than in US Common law jurisdictions.57 Louisiana, like the other mixed systems studied, has no mutual consid­ eration doctrine, and it recognises the validity of irrevocable offers,58 both of which solve some problems which promissory estoppel deals with in Common law systems. In the 1950s the Louisiana Supreme Court denied that there was any such doctrine as promissory estoppel in Louisiana law.59 However, in the 1984 Codal revision a provision on detrimental reliance on a promise (in effect, promissory estoppel) was introduced. Article 1967 of the Civil Code provides that a party ‘may be obligated by a promise when he knew or should have known that the promise would induce the other party to rely on it to his detriment and the other party was reasonable in so relying’, though adding that reliance on a gratuitous promise lacking required formalities is not reasonable.60

While the need for a general doctrine of promissory estoppel in Louisiana law is questionable,61 Article 1967 is clearly capable of explain­ ing liability in circumstances in which no valid contractual renunciation has occurred but rights have been waived by one contracting party and such waiver has been relied upon by the other party.

56‘It is repeatedly emphasised by our courts that evidence of an alleged waiver of rights is required, particularly where an implied waiver has been made. It should be clear that the person acted with due notice of his rights and that his actions are inconsistent with the continued existence of such rights or with intent to enforce them’ (per Corbett AJA, in Borstlap v. Spangenberg 1974 (3) SA 695, 704 (A), my translation from the Afrikaans).

57See further Snyder, ‘Hunting Promissory Estoppel’.

58 CC Art. 1928.    59  Ducote v. Oden 59 So 2d 130, 132 (La 1952).

60Which contrasts with the statutory provisions on personal bar in Scots Law, which spe­ cifically permit reliance on a gratuitous promise lacking the proper formalities to found a claim of personal bar: see Requirements of Writing (Scotland) Act 1995, s. 1(3), (4).

61Though the provision has been used to explain, inter alia, certain commercial trans­ actions, such as the so-called ‘estoppel letters’ which are used to elicit promises from businesses that they do not object to a planned merger: see Snyder, ‘Hunting Promissory Estoppel’, p. 310, who suggests that the Scottish unilateral promissory approach would be a preferable analysis of such transactions.