"where the property comprised in the tenancy is or includes premises which are occupied by the tenant and are so occupied for the purposes
"a tenancy created either immediately or derivatively out of the freehold, whether by lease or underlease, by an agreement for a lease or underlease or by a tenancy agreement ..."
"(1) A tenancy to which this part of this Act applies shall not come to an end unless terminated in accordance with the provisions of this Part of this Act: and, ... the tenant under such a tenancy may apply to the court for a new tenancy -
"(1) The obligation under a condition or of a covenant entered into by a lessor with reference to the subject matter of the lease shall, if and as far as the lessor has power to bind the reversionary estate immediately expectant on the term granted by the lease, be annexed and incident to and shall go with that reversionary estate . . . and may be taken advantage of and enforced by the person in whom the term is from time to time vested . . . and ... the obligation aforesaid may be taken advantage of and enforced against any person so entitled."
"The contractual obligations which touch and concern the land having become imprinted on the estate, the tenancy is capable of existence as a species of property independently of the contract."