Editing Patentability (section)

== Opposition and reexamination ==

Many national and regional patent offices provide procedures for reconsidering whether or not a given patent is valid after grant. Under the [[European Patent Convention]], any person can file an [[Opposition procedure before the European Patent Office|opposition]] provided they act promptly after the patent is granted. In the United States, members of the public can initiate [[reexamination]] proceedings. Japan provides similar options. In India, the Patent Act provides for a dual opposition system i.e. pre-grant opposition as well as post grant opposition. While a pre-grant opposition may be filed by any person, the post grant opposition may only be filed by a person interested in the field of invention.<ref>{{Cite web|url=http://www.ipindia.nic.in/writereaddata/Portal/ev/sections/ps25.html|title=Opposition Proceedings to Grant of Patents}}</ref>

Members of the public can also initiate [[lawsuit]]s in the courts of various nations to have patents declared invalid.

United Kingdom patents can be reviewed by way of a [[Non-binding opinion (United Kingdom patent law)|non-binding opinion]] issued by the Patent Office, or by formal applications for revocation before the Patent Office or the Court. If the patent survives a revocation action, this fact is noted for future reference by way of a [[Certificate of contested validity]].