P was the guardian of X and had borrowed money to educate her etc. X’s husband, D, undertook to repay P what he had borrowed to bring up X (previously it had been X herself repaying P). He failed to do so. The court ruled that conferring a benefit on someone voluntarily, which they did not ask for, is not enough to found a contract even when supported by subsequent promise.
Lord Denman: even if the expense had been at the request of X, there still would be no contract since “past consideration is no consideration at all”. This rule “must be made absolute” and that past consideration creates only moral, NOT contractual, obligation.