What is the current state of the law on the covenant of quiet enjoyment between a landlord and a tenant?

Within the context of a landlord/tenant relationship, the covenant of “quiet enjoyment” protects the tenant’s right to freedom from serious interferences with his or her tenancy. In a case within which similar conduct was considered, it was held that a landlord can be insistent and persistent and even rude in taking measures provided by the law to pursue his right to evict for a serious breach by a tenant. However, when there is an element of direct physical interference by repeatedly knocking on the door and shouting threats, that element of direct physical interference is not trivial, but substantial. [See Kenny v. Preen (1963) 1 QB 499, (1962) 3 All ER 814 (C.A.)].