In a surprising decision, the Supreme Court decided by a majority of 3-2 that "this is a straightforward case of nuisance." Visual intrusion can amount to an actionable nuisance where there is a substantial interference with the ordinary use and enjoyment of the property.
In this case, the claimants' flats "are under constant observation from the Tate's viewing gallery for much of the day, every day of the week; that the number of spectators is in the hundreds of thousands each year" and "it is not difficult to imagine how oppressive living in such circumstances would feel for any ordinary person – much like being on display in a zoo."
However, the Supreme Court did not make a decision on the appropriate remedy and referred the matter back to the High Court to decide. The Supreme Court did however say that it suspected that the reason for the court's decision below was a "reluctance to decide that the private rights of a few wealthy property owners should prevent the general public from enjoying an unrestricted view of London and a major national museum from providing public access to such a view." and, if this is relevant, it is relevant to the issue of remedy.
It remains to be seen whether a settlement will be reached between the parties which will allow part of the viewing gallery to remain open even if subject to certain restrictions. The Supreme Court did highlight that "the claimants cannot be obliged to live behind net curtains."