A builder agrees to complete work for a fixed price. Midway, the client, worried about delay penalties under its own contract, promises extra payment if the builder finishes on time. The builder does so. Under English law, which case most supports the builder enforcing the extra payment?

Correct answer: B) Williams v Roffey Bros, because the client obtained a practical benefit and there was no duress

Explanation

Performing an existing contractual duty owed to the promisor is generally not good consideration (Stilk v Myrick). However, Williams v Roffey Bros held that where the promisor obtains a practical benefit, such as avoiding a penalty clause, and there is no economic duress or fraud, the promise of extra payment can be enforced. Foakes v Beer concerns part payment of debts.