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This case (Combe v Combe [1951] 2 KB 215) was brought on the strength of the High Trees House case (see: Central london property trust ltd v high trees ltd (1947)) and may be seen as an attempt to exploit the recently-created precedent of that case in a way for which it was never really intended. However, the reasons why Promissory estoppel could be used by High Trees and not by Combe are not all that clear at first sight and, indeed, the judge in the first instance ruled that it was applicable. The ruling was overturned by the Court of Appeal, as will be explained below.

Before their divorce, Mr Combe promised to pay Mrs Combe an annual amount for maintenance. Sadly, after the divorce he declined to pay. Mrs Combe sued Mr Combe for an order to enforce the promise. Clearly there was no Consideration that would support the promise as a contract, Mrs Combe's defence was on the basis of estoppel. Her argument was that he had made a promise, she had acted on it (by, for example, not seeking a maintenance order from the courts), and that action had been to her detriment.

The court in the first instance accepted this argument, but the Court of Appeal reversed it. The argument was that this was an attempt to use estoppel as a sword, not a shield. In the HT case, HT were in an existing contractual arrangement with Central London Property Trust (CLPT). CLPT's breach of promise was an attack on an existing agreement, and estoppel could be used to defend against it. However, Mrs Combe was using estoppel in attack, creating a legal case where none existed before.