Final answer:
Not all collateral promises need to be in writing to be enforceable, primarily due to exceptions like the main purpose rule, part performance, and promissory estoppel.
Step-by-step explanation:
Not all collateral promises are required to be in writing to be enforceable, according to the Statute of Fra uds. Generally, a collateral promise, which is a secondary promise to answer for the debt or duty of another, must be in writing to be legally binding, as mandated by the Statute of Frauds. However, there are exceptions to this requirement. For instance, if the main purpose of the promisor is to secure a personal benefit, rather than guaranteeing another's debt, the promise may be enforced even if it is not written. Furthermore, if one of the parties to the contract has partly performed the promise, a court may enforce the oral collateral promise under the doctrine of part performance. Another exception includes situations where the creditor has relied on the promise to their detriment, also known as promissory estoppel.