Facts: By contract, the sellers agreed to sell 250 tons of coffee beans at 262 Kenyan shillings per cwt (i.e. per hundredweight) to El Nasr payable on credit. At the time of the contract the value of Kenyan shillings and pound sterling were of equal value. Whilst the contract stipulated the price payable in Kenyan shillings, the credit account referred payment in pound sterling. There were a number of other discrepancies between the credit agreement and contract such as date of shipping and the quantity to be shipped. These other discrepancies were rectified in a revised agreement however, the new agreement still referred to payment in pound sterling. The sellers accepted the first instalment of 57,000 in pound sterling without objection, however, the value of the pound dropped quite dramatically resulting in a loss of 165,530.45 shillings. The sellers then sought to revert to Kenyan shillings and demanded the further payment. The buyers raised promissory estoppel in their defence in that in accepting the instalment in pound sterling and redrafting the credit agreement without changing the currency there was an implied promise that they would not revert to Kenyan Shillings. The sellers argued that the buyers had not acted to their detriment in reliance of this promise as they had gained a benefit.

Held: Detrimental reliance is not a requirement of promissory estoppel. It only needs to be established that the promisor has changed their position.

Facts: The plaintiffs (i.e. claimants) owned some flats and rented them to the defendants for £2500 per year. When WW2 started the defendants could not find people wanting to buy the flats. So, the plaintiffs agreed to half the rent the defendants were paying, which continued throughout the war. After the war, the plaintiffs wanted to put the rent back up to £2500 per year and also acted to claim the half of the money not paid in the war years as there had been no consideration for that change of contract.

Held: The rent could be increased back to £2500 per year, but could not claim back the arrears accrued during the war years.

⇒ It was stated obiter (i.e. a non-binding part of the judgement) that if we were to follow Foakes v Beer - which tells us that part-payment of debt is not good consideration - then accepting a lower rent during the war years is not enforceable, enabling them to recover the arrears accrued throughout the war

⇒ However, despite this, Denning was willing to say a promise could be enforceable, which was a controversial decision at the time. He said that "a promise intending to be binding, intending to be acted on and in fact acted on, is binging so far as its terms properly apply". So, the money from the war years could not be recovered

• So even though the defendants did not provide consideration for the plaintiff's promise to accept half rent, this promise was intended to be binding and was acted on by the defendants. Therefore the plaintiffs were estopped from going back on their promise and could not claim the full rent for the war years

Facts: A husband promised to make maintenance payments to his estranged wife but failed to do so. The wife brought an action to enforce the promise invoking promissory estoppel.<

Held: Her action failed. There was no pre-existing agreement which was later modified by a promise. The wife sought to use promissory estoppel as sword and not a shield.

Facts: Mr Rees instructed the claimant to do some building work at his home to the value of £746. Mr Rees paid £250 on account and the claimant reduced the bill by £14 and there was a sum owing of £482. The claimant wrote to the defendant several times pressing for payment but was unsuccessful there had been no complaints as to the workmanship at this time. The claimant at the time was in dire financial need and the business was verging on bankruptcy a fact that Mrs Rees was aware of. The defendant telephoned the home and Mrs Rees answered she made complaints about the work and said she would give them £300 in satisfaction of the whole debt. The defendant refused and said he would take the £300 and give her a year to clear the balance. He called at the house to collect the money but Mrs Rees remained firm that she would only pay £300 and demanded that the defendant wrote on the receipt 'in completion of the account' otherwise she would pay him nothing. The defendant needed the money immediately so reluctantly agreed to write this on the receipt but stated he fully intended to pursue the balance as the money paid did not cover the costs he had incurred. He subsequently brought an action to recover the balance. The defendant sought to rely on estoppel relying on the written receipt as demonstrating a promise to accept the lesser sum.

Held: The claimants were successful. Mrs Rees could not rely on estoppel as there was no true agreement to accept less and because Mrs Rees had taken advantage of the builder's position and mislead them as to her financial position.

Facts: The defendant has a house leased from the plaintiff (i.e. claimant). In the lease there was a clause requiring the defendant to make repairs to the property if the plaintiff asks for them to be done. The plaintiff wanted some repairs done and gave the defendant six months to do so. The defendant and plaintiff then negotiated about the possibility of the sale of the house from the plaintiff to the defendant, but these negotiations later broke down. The repairs had not been made because the defendant thought he would be able to buy the house. The plaintiff then, because of this, wanted to take possession of the property back.

Held: The plaintiff "waived" the requirement for the repairs during the negotiation for the sale of the property due to an implied promise that this would be the case. So, the House of Lords called this “equitable waiver” – where a promise is binding even without consideration

Facts: Tungsten had infringed on Tool Metal Manufacturing Co's (TMM) patent right. When TMM heard of this they waived the infringement as Tungsten paid 10% Royalty and also 30% 'compensation' if their sales were over 50kg in a month. This was quite a lot but Tungsten agreed, however they found it hard to make payments. During the war they were in particular difficulty so TMM waived the requirement for the compensation payment during the war.

Held: Usually promissory estoppel will suspend rights but here there were pressing circumstances on Tungsten which were likely to persist so promissory estoppel could extinguish the right for them to pay the compensation to TMM

Facts: A contract for the sale of some coffee beans was agreed to be payable in pound sterling. The sellers mistakenly sent an invoice stating price was payable in Kenyan Shillings. At the time the value of pound sterling and Kenyan shillings was equal. The buyers accepted the delivery and invoice with out objection. Subsequently the value of the pound fell quite dramatically in relation to Kenyan shillings. The buyers then sought to revert to pound sterling as stated in the contract.

Held: The buyers conduct in accepting the invoice unquestionably amounted to an implied clear and unambiguous promise to accept on those terms.