This is a notice by a Landlord that they do not intend to renew a ‘renewable’ lease. It is also a notice to charge mesne profits (double rent) if the tenant does not vacate.
It is used where the Landlord wants to regain possession of property e.g. for redevelopment, if the property has been sold, if the tenant has been in breach etc.
It is served upon the Tenant before expiry of the lease.