Overview
Power and Kyson v Shah is now one of the most important modern party wall cases.
The principle is blunt: no notice, no Act.
The question
Can the Party Wall etc. Act 1996 be invoked retrospectively where works have already been carried out and no notice was served by the building owner?
The decision
The court said no. Without a building owner's notice, the Act is not engaged in the way required to give surveyors jurisdiction to make a statutory award.
An adjoining owner cannot unilaterally create a retrospective party wall process after the event.
Why it matters
This narrows a practical route that some surveyors used to resolve messy post-work disputes cheaply.
If works are carried out without notice, the adjoining owner may be pushed toward common law routes such as trespass, nuisance, negligence or an injunction, rather than a normal statutory award.
For building owners
Serving notice remains the sensible and cheaper route. If you do not serve notice, you may lose the protection and structure of the Act and expose yourself to court proceedings.
For adjoining owners
If notifiable works start without notice, act early. Delay can reduce practical options and make the dispute harder to control.
A prompt letter, proper evidence and early advice are usually more useful than waiting until the works are complete.