83. Amendment of patent in infringement or revocation proceedings, etc.

In any proceedings before the court or the Registrar in which the validity of a patent is put in issue, the court or, as the case may be, the Registrar may, subject to section 84, allow the proprietor of the patent to amend the specification of the patent in such manner, and subject to such terms as to the publication and advertisement of the proposed amendment and as to costs, expenses or otherwise, as the court or Registrar thinks fit.

A person may give notice to the court or the Registrar of the person’s opposition to an amendment proposed by the proprietor of the patent under this section, and if the person does so the court or the Registrar must notify the proprietor and consider the opposition in deciding whether the amendment or any amendment should be allowed.

An amendment of a specification of a patent under this section has effect and is deemed always to have had effect from the grant of the patent.

Where an application for an order under this section is made to the court, the applicant must notify the Registrar, who is entitled to appear and be heard and must appear if so directed by the court.