#consideration #contract

Facts: Woodhouse (the appellant buyers) purchased cocoa from the respondent sellers (Nigerian Produce) and the price was to be paid in Nigerian pounds in Lagos. The buyers then asked, by letter, if the sellers would agree to accept sterling in Lagos. The sellers agreed, by letter dated 30 September 1967, that payment could be made 'in sterling and in Lagos'. The pound sterling was then devalued so that it was worth less than the Nigerian pound. The buyers claimed that they could pay one pound sterling to one Nigerian pound. The sellers disagreed. One of the arguments raised by the buyers was that the representation contained in the letter dated 30 September 1967 amounted to an estoppel meaning that the sellers could not go back on it and claim the full price for the contracts.
The letter did not unambiguously state that the price to be paid would be Nigerian pounds for pounds sterling. In order to give rise to an estoppel a promise must be clear and unequivocal. The letter amounted only to a representation that the seller would accept payment in pounds sterling, rather than the Nigerian pound, to the same value as had been agreed. Lord Hailsham LC in particular made it plain that, if a promise would be insufficiently clear to vary the contract, such a promise could not be sufficiently clear to found the defence of promissory estoppel.

Woodhouse A.C Israel Cocoa Limited S.A and Another v Nigerian Produce Marketing Co Limited [1972] AC 741