How to manage your patents

Post-grant opposition of patents


If you believe a patent should not have been granted, there are limited ways in which you can challenge the patent's validity. You can request an opinion from the Intellectual Property Office (IPO) or file an opposition in court to try to invalidate or revoke a patent.

Litigation in court is generally more expensive, time-consuming and stressful than some of the other ways of resolving patent disputes.

Opinions on entitlement or validity

If you believe a patent is invalid or infringes earlier rights, you don't automatically need to begin legal proceedings. You can ask for the UK IPO's patent opinion.

As part of the opinion process, the IPO's senior examiners can look into the validity or infringement of:

  • your own patent
  • someone else's patent
  • supplementary protection certificates (pharmaceutical industry)

An opinion is not binding on you or others involved, however can help you negotiate a settlement or decide if it's worth your while taking legal action.

The opinion process typically takes around three months and costs £200. The opinion can conclude that:

  • a particular act infringes the patent
  • there is no infringement
  • the IPO consider the patent invalid - if so, they may decide to revoke a patent

When the IPO reach an opinion, they will send it to all the parties involved in the case and will advertise the outcome. Read more about opinions as a way of resolving patent disputes.

Actions following issue of an opinion

If you disagree with the IPO's opinion, you may be able to challenge it and request a review if you are either:

  • the patent holder
  • the supplementary protection certificate proprietor
  • an exclusive licensee

As part of the review, the IPO will conduct full legal proceedings and can either confirm their decision or set it aside. At this point, you may be able to amend your patent to overcome the issues raised, to avoid revocation. In limited circumstances, you may be able to appeal the review decision further. 

Ways to revoke or invalidate a patent

A UK patent can be revoked by the UK IPO or the court. Defendants in infringement actions often bring revocation as counter claims in the legal process. If your patent is revoked, it will be treated as never having existed.

Under UK patent law, there are five main grounds for revocation of a patent:

  1. Non-patentability: the invention isn't novel or lacks the inventive step, or is related to excluded subject matter (eg medical treatment).
  2. Non-entitlement: the patent was granted to a person who was not entitled to it.
  3. Insufficiency: the patent specification doesn't disclose the invention clearly enough for a skilled person to be able to put it into use.
  4. Added matter: the subject-matter of the patent extends beyond the content of the originally filed application.
  5. Unallowable post-grant extension: the protection granted by the patent has been extended by an amendment after grant which should not have been allowed.

Read more about the power to revoke patents on application.

Opposing requests for changes to a patent

Sometimes people ask to make changes to their patent after it has been granted. The IPO publishes these requests, and you can object to them just as you can object to an original patent application.