The remedy for promissory estoppel is reliance damages. A promissory note alone is typically unsecured. The doctrine of promissory estoppel may not make the total contract fully enforceable. In English law, proprietary estoppel is distinct from promissory estoppel. This can occur with all debt obligations including bonds, mortgages, loans, and promissory notes. Modern contract theory has also permitted remedies on alternative theories such as promissory estoppel. Capital projects were paid for with the issuance of promissory notes called Mefo bills. The wife brought an action to enforce the promise invoking promissory estoppel. In English law, "proprietary estoppel" is distinct from promissory estoppel. A promissory note is very similar to a loan. Promissory notes may be used in combination with security agreements. The case was the first known instance of the concept of promissory estoppel. The doctrine of promissory estoppel was adopted into Australian law in "Legione v Hateley". This development required the acceptance in trade of the goldsmiths' promissory notes, payable on demand. Financial institutions transferred their money to the Finance Department in exchange for promissory notes.