A subletting takes place when a tenant grants a new lease for their property, or part thereof, to an alternative occupier, for a period less than the residue of the tenant’s lease. The period of the subletting must be at least one day less than the unexpired period of the superior lease. If a tenant attempts to sub let the property for a period equal to, or more than, the unexpired period of their own lease; this operates as an assignment of the term and not as a subletting.

It differs from assignment in that the head lessee remains responsible to the landlord for the payment of rent and fulfillment of other obligations.