31.—(1) The undertaker may compulsorily acquire so much of, or such rights in, the subsoil of the land within the permanent limits as may be required for any purpose for which that land may be acquired instead of acquiring the whole of the land.
(2) Where the undertaker acquires any part of, or rights in, the subsoil of land under paragraph (1) the undertaker cannot be required to acquire an interest in any other part of the land.
(3) Paragraph (2) does not prevent article 37 (acquisition of part of certain properties) from applying where the undertaker acquires a cellar, vault, arch or other construction forming part of a house, building or manufactory.