In Kenny v Preen  1 QB 499, Pearson LJ in the Court of Appeal said (at 511):
The implied covenant for quiet enjoyment is not an absolute covenant protecting a tenant against eviction or interference by anybody, but is a qualified covenant protecting the tenant against interference with the tenant’s quiet and peaceful possession and enjoyment of the premises by the landlord or persons claiming through or under the landlord. The basis of it is that the landlord, by letting the premises, confers on the tenant the right of possession during the term and impliedly promises not to interfere with the tenant’s exercise and use of the right of possession during the term. I think the word “enjoy” used in this connection is a translation of the Latin word “fruor” and refers to the exercise and use of the right and having the full benefit of it, rather than to deriving pleasure from it.
It was previously thought that a covenant for quiet enjoyment is only breached if the title or possession of the land is affected. However, in Harrison, Ainslie & Co v Muncaster  2 QB 680, the
UK Court of
Appeal held that (at 684):
Formerly it was thought that a covenant for quiet enjoyment only applied to an interference with the title of the covenantee, but upon more careful consideration it was held that it applied to an interference with the enjoyment of the thing demised; and it seems clear that there may be an interference with the enjoyment of property without any interruption to or interference with the title to it
Whether this interference has taken place is, in each case, a question of fact. In Owen v Gadd  2 QB 99, the
UK Court of
Appeal said (at 105):
The question whether the quiet enjoyment of the premises demised has been interrupted or not is in every case one of fact; and the covenant is broken although neither the title to the land nor the possession of the land may be otherwise affected, where the ordinary and lawful enjoyment is substantially interfered with by the acts of the lessor or of those lawfully claiming under him.