The common law doctrine of frustration and the civil law doctrine of force majeure are both doctrines of respectable antiquity that can trace their origins back to Roman law. The recent Coronavirus pandemic (and its unprecedented impact on business) has focused attention on the way in which these doctrines have been developed by courts in different jurisdictions and prompted debate as to whether such developments now strike the right balance between legal certainty on the one hand, and fairness to the contracting parties on the other. Given Jersey’s unique status as a “mixed” civil and common law jurisdiction, a comparison of English law and French law in this area offers some interesting insights into the likely scope of a modern Jersey customary law doctrine of force majeure.