It is only available to former leaseholders in the context of leases created after the enactment of the Landlord and Tenant (Covenants) Act 1995

It is only available to former leaseholders in the context of leases created before the enactment of the Landlord and Tenant (Covenants) Act 1995, as a way of mitigating the severity of their enduring contractual liability

An overriding lease results in the existing tenancy of the defaulting tenant becoming a sub-tenancy, and the previous leaseholder becomes both the immediate landlord of the defaulting tenant, and the immediate tenant of the original landlord

The ability to request an overriding interest is an option available to relevant leaseholders, but any request made to the landlord can be refused by that landlord for any reason deemed objectively reasonable

It is only available to the immediately preceding leaseholder