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Survey of the IPO opinions service

Date: 16 August 2023

The UK’s Intellectual Property Office (‘IPO’) can be asked, for a small fee, to give an opinion on the validity or infringement (or both) of a UK patent or UK registration of a European patent. This can be a useful low-cost, low-risk tool for negotiation purposes. Edward Belknap surveys recent IPO opinions.


Opinions are carried out by senior examiners on request, based on documents provided with the request. They are non-binding both on the person requesting the opinion and on third parties. They do not involve the courts, meaning costs are greatly reduced when compared to legal proceedings. This service is open to everyone.

The IPO opinions service is a useful way of gaining a preliminary assessment on whether to pursue further legal action without having to expend great effort and cost in the courts. The patent proprietor or a third party can challenge an opinion and apply for it to be reviewed by commencing proceedings at the IPO (or of course by bypassing the IPO and proceeding directly to the Patents Court). The examiner can refuse to give a validity opinion based on prior art already considered during examination, grounds that are not valid grounds for invalidity, or issues that have already been considered in other proceedings. The request must have sufficient information to be able to render a sensible opinion, and vexatious or frivolous requests can also be refused.

Infringement opinions only give an initial analysis for infringement and do not result in settlements. Validity opinions, on the other hand, can result in the revocation of the patent in question. Revocation of a patent under the Comptroller’s initiative can only occur once the patent proprietor has been given the opportunity to make observations or amendments to the patent in question.


‘Most requests for infringement opinions are filed by the proprietor of the
patent in question.’



Survey of recent IPO opinions


From 2021 to 2022, 50 requests for patent opinions were filed at the IPO:


  • 30 concerned questions on validity, of which 13 patents were found to be at least partially invalid;
  • 18 concerned questions on infringement, of which seven patents were found to be at least partially infringed; and
  • two concerned both validity and infringement, of which the two patents were found to be at least partially infringed.


In some cases, the examiner did not consider that revocation would be appropriate, notwithstanding invalidity of the patent. In each case, the proprietor was invited to file amendments instead.


That being said, one patent was indeed revoked after the patent proprietor did not take any action after a negative validity opinion was issued. Before revocation, the examiner issued a warning that the patent would be revoked unless action was taken. This, however, rarely happens, as there is an opportunity for observations and amendments to be filed in response to a negative validity opinion.


Most requests for infringement opinions are filed by the proprietor of the patent in question. Occasionally (about one in four cases), a third party may request an opinion on infringement in order to show non-infringement. For example, a request for an infringement opinion was filed in 2021 by attorneys at Maucher Jenkins on behalf of a third party seeking a non-infringement decision. The examiner sided with the third party and issued an opinion which concluded no infringement had or would occur. Opinions like these are valuable for third parties when encountering potential infringement situations.

In some circumstances, it can be advantageous for patent proprietors to file requests for validity opinions. For example, an infringement opinion in 2022 was requested by a proprietor and it was found that the patent was infringed. The proprietor then requested another opinion on validity (perhaps certain prior art was brought to the proprietor’s attention, but this is speculation). This second opinion found that the patent was invalid. This put the proprietor in an advantageous position, as they would have been able address the validity issues to ensure that the patent is valid before starting infringement proceedings.

Opinions therefore offer helpful indications on different options and routes when dealing with validity and infringement. Proprietors should be diligent in both validity and infringement proceedings in order to address any issues that arise, for example in good time before the IPO considers revocation as a possibility.




  1. www.gov.uk/guidance/opinions-resolving-patent-disputes
  2. www.gov.uk/government/collections/requests-for-opinions 
  3. www.gov.uk/government/publications/opinions-manual/opinions-manual 



Edward Belknap is a Trainee Patent Attorney at Maucher Jenkins.