354. Qualifications.

To qualify, the tenant must be a tenant of a flat1 under a long lease2. A 'tenant' includes a person holding a lease or tenancy, or an agreement for a lease or tenancy, and includes sub-leases and sub-tenancies3. Joint leaseholders are treated as one tenant4. A 'long lease' is one which is granted for a term of years certain exceeding 21 years, whether or not it is terminable before the end of that term5. The definition also includes most perpetually renewable leases, leases terminable by death or marriage, and leases granted under right to buy provisions and shared ownership