Section 17 of the Principal Act is amended -
(a) by the substitution of the following for subsection (1A) (inserted by the Finance Act, 1986):
(a) An invoice or other document required to be issued by a person under this section shall, subject to paragraph (b), be deemed to be so issued by that person if the particulars which are required by regulations to be contained in such invoice or other document are recorded, retained and transmitted electronically by a system or systems which ensures the integrity of those particulars and the authenticity of their origin, without the issue of any invoice are other document containing those particulars.
(b) An invoice of other document required to be issued under this section shall not be deemed by paragraph (a) to be so issued unless the person, who is required to issue such invoice or other document, complies with such conditions as are specified by regulations and the system or systems used by that person conforms with such specifi