(1)Every claim of a complete specification shall have effect from the date prescribed by this section in relation to that claim (in this Act referred to as the priority date); and a patent shall not be invalidated by reason only of the publication or use of the invention so far as claimed in any claim of the complete specification, on or after the priority date of that claim, or by the grant of another patent upon a specification claiming the same invention in a claim of the same or later priority date.
(2)Where the complete specification is filed in pursuance of a single application accompanied by a provisional specification or by a specification which is treated by virtue of a direction under subsection (4) of section three of this Act as a provisional specification, and the claim is fairly based on the matter disclosed in that specification, the priority date of that claim shall be the date of filing of the application.
(3)Where the complete specification is filed or proceeded with in pursuance of two or more applications accompanied by such specifications as are mentioned in the last foregoing subsection, and the claim is fairly based on the matter disclosed in one of those specifications, the priority date of that claim shall be the date of filing of the application accompanied by that specification.
(4)Where the complete specification is filed in pursuance of a convention application and the claim is fairly based on the matter disclosed in the application for protection in a convention country or, where the convention application is founded upon more than one such application for protection, in one of those applications, the priority date of that claim shall be the date of the relevant application for protection.
(5)Where, under the foregoing provisions of this section, any claim of a complete specification would, but for this provision, have two or more priority dates, the priority date of that claim shall be the earlier or earliest of those dates.
(6)In any case to which subsections (2) to (5) of this section do not apply, the priority date of a claim shall be the date of filing of the complete specification.