Rei interitus (in the context of a lease) meaning

In lease practice, rei interitus describes automatic termination of the lease, releasing landlord and tenant from future obligations (including rent and possession), where the leased subjects are, without either party’s fault, destroyed or so damaged that they are no longer tenantable. The term is a Scots law doctrine developed in case law, not statute. Rei interitus arises on total or constructive destruction caused by damnum fatale (for example, accidental destruction by fire or overblowing by sand) or by requisition under statutory authority. It does not cover purely commercial loss, such as the loss of a hotel licence. Where the damage is attributable to an act of God and the lease does not allocate liability for that risk, the landlord is not obliged to carry out repairs or reinstatement. In England & Wales, Northern Ireland and Ireland the label is not used; the equivalent question is addressed under the common law doctrine of frustration, which may discharge a lease on destruction or permanent untenantability but only in exceptional circumstances. Modern insurance, rent cesser, reinstatement and termination clauses commonly govern outcomes across all jurisdictions. Practically, parties should allocate the risk of accidental destruction, insurance proceeds, rent suspension and termination rights expressly.