In upholding a listed building enforcement notice directed at the replacement of a window at a 17th century farmhouse in Cheshire with French doors (DCS Number 400-031-136) an inspector rejected the appellant’s argument that the notice should be considered a nullity as it required the installation of a window that would not comply with Building Regulations.
The inspector accepted that the Building Regulations set standards for design and construction that apply to most new buildings and many alterations to existing buildings. She explained, however, that there is no general requirement to upgrade all existing buildings to meet these standards. The reinstatement of a window to replicate what existed previously would mean that the building’s compliance with the Regulations would be no more unsatisfactory, she reasoned.
Even if she were to accept the appellant’s argument on the matter, the inspector continued, case law has established that such circumstances would not mean the notice was ultra vires. She recorded that in McKay v SSE  a notice which was valid on its face included requirements which would themselves have been a breach of Section 2 of the Ancient Monuments and Archaeological Areas Act 1979, and so a criminal offence. Therefore, It was held to be a nullity and so not correctable or variable. Subsequently, however, in the case of South Hams DC v Halsey  , the Court of Appeal specifically disagreed with the decision in McKay. The Court held that if the requirements of a notice did put the recipient in that position, which he was unable to resolve, he would have a defence to the notice if prosecuted. Such a notice was therefore valid and not a nullity.
Immunity from enforcement is covered at section 4.535 of DCP Online.