Sch FIRST Pt V para 1
Where, immediately before the commencement of this Act, a party wall or other party structure is held in undivided shares, the ownership thereof shall be deemed to be severed vertically as between the respective owners, and the owner of each part shall have such rights to support and of user over the rest of the structure as may be requisite for conferring rights corresponding to those subsisting at the commencement of this Act.