(1)Any person may at any time within two months from the date of the advertisement of the acceptance of a complete specification give notice at the Patent Office of opposition to the grant of the patent on any of the following grounds:—
(a)that the applicant obtained the invention from him, or from a person of whom he is the legal representative ; or
(b)that the invention has been claimed in any complete specification for a British patent which is or will be of prior date to the patent the grant of which is opposed, other than a specification deposited pursuant to an application made more than fifty years before the date of the application for such last-mentioned patent ; or
(c)that the nature of the invention or the manner in which . it is to be performed is not sufficiently or fairly described and ascertained in the complete specification ; or
(d)that the complete specification describes or claims an invention other than that described in the provisional specification, and that such other invention forms the subject of an application made by the opponent in the interval between the leaving of the provisional specification and the leaving of the complete specification,
but on no other ground.
(2)Where such notice is given the comptroller shall give notice of the opposition to the applicant, and shall, on the expiration of those two months, after hearing the applicant and the opponent, if desirous of being heard, decide on the case.
(3)The decision of the comptroller shall be subject to appeal to the law officer, who shall, if required, hear the applicant and the opponent, if the opponent is, in his opinion, a person entitled to be heard in opposition to the grant of the patent, and shall decide the case ; and the law officer may, if he thinks fit, obtain the assistance of an expert, who shall be paid such remuneration as the law officer with the consent of the Treasury may determine.