23Limited prohibition on assignation etc. without consent
(1)Subject to subsection (2) below, it shall be an implied term of every assured tenancy that, except with the consent of the landlord, the tenant shall not—
(a)assign the tenancy (in whole or in part); or
(b)sublet or part with possession of the whole or any part of the house let on the tenancy.
(2)Subsection (1) above does not apply if, under the terms of the tenancy, there is provision prohibiting or permitting (whether absolutely or conditionally) assignation, subletting or parting with possession by the tenant.