Patent Revocation Solicitors

A granted patent is not untouchable. Where a patent should not have been granted — because the invention lacked novelty, was obvious, or was insufficiently disclosed — it can be challenged and revoked. Freeman Harris acts for businesses and individuals on both sides of revocation proceedings: those seeking to clear a competitor’s patent from the market, and those defending the validity of their own IP.

Our patent team is led by David Sant, a Solicitor-Advocate (England & Wales), Solicitor (Ireland), and European Patent Attorney before the EPO, with over 30 years’ experience across the full spectrum of patent work — from prosecution and EPO oppositions through to High Court litigation and licensing. David began his career as a patent examiner in Physics at the EPO in Munich and has since conducted contentious and non-contentious patent work at the highest level. Where a question of validity arises — whether as a standalone challenge or as a counterclaim to an infringement action — we advise on the strongest available grounds and the most appropriate forum.

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What is Patent Revocation?

Revocation is the legal process by which a granted patent is declared invalid and removed from the register. A revoked patent is treated as if it never existed — meaning any infringement claims based on it fall away, and any licences granted under it may be affected.

Revocation can be pursued as a standalone action or raised as a defence and counterclaim in response to a patent infringement claim. It is one of the most powerful tools available to a defendant facing allegations of patent infringement, and equally important for businesses that need freedom to operate in a market dominated by a competitor’s patent portfolio.

Grounds for Revocation Under UK Law

Under section 72 of the Patents Act 1977, a patent may be revoked on the following grounds:

Lack of Novelty

The invention was already known — whether through a prior published document, an earlier patent, or use in public — before the priority date of the application. A single piece of prior art that discloses all the features of the claimed invention is sufficient to destroy novelty.

Obviousness (Lack of Inventive Step)

Even if the invention was not previously known in exactly the form claimed, it would have been obvious to a skilled person in the relevant field. This is one of the most commonly argued grounds and requires a careful assessment of what was known at the priority date and what a skilled addressee would have done.

Insufficiency of Disclosure

The patent specification does not disclose the invention clearly and completely enough for a skilled person to reproduce it. If the specification is ambiguous, contains errors, or fails to enable the full scope of the claims, the patent may be revoked for insufficiency.

Added Matter

The claims or description were amended after filing in a way that adds subject matter not disclosed in the original application. Post-filing amendments are tightly controlled, and any broadening beyond what was originally filed provides grounds for revocation.

Not a Patentable Invention

The invention falls outside the scope of what is patentable — for example, because it is a discovery, a mental act, a computer program as such, or a method of treatment of the human body.

Revocation Forums: Choosing the Right Approach

There are several forums in which patent validity can be challenged. The right choice depends on the scope of the patent, the urgency of the challenge, and the costs involved.

UKIPO Revocation Proceedings

The UK Intellectual Property Office (UKIPO) offers a cost-effective route for challenging patent validity without going to court. Proceedings before the UKIPO are generally less expensive than court litigation, making them an accessible first option — particularly for smaller businesses. The UKIPO can hear cases on all grounds under section 72.

Intellectual Property Enterprise Court (IPEC)

IPEC is a specialist court within the Business and Property Courts, designed to handle IP disputes in a proportionate and cost-effective way. Costs are capped at £60,000, and damages at £500,000. IPEC is well-suited to revocation claims of moderate complexity and to invalidity counterclaims in lower-value infringement disputes.

Patents Court (High Court)

For high-value or technically complex revocation proceedings, the Patents Court provides the most comprehensive forum. There are no financial caps, and the court has significant experience handling technically demanding cases. Where a patent has significant commercial value to the patentee, proceedings in the Patents Court are typically required.

European Patent Office (EPO) Opposition

A European patent can be opposed before the European Patent Office within nine months of grant. EPO opposition is a cost-effective means of challenging a European patent across all its designated states in a single action. David Sant conducts EPO opposition and appeal proceedings directly. He began his career as a patent examiner in Physics at the EPO in Munich, and has extensive personal experience of opposition procedure before the EPO throughout his career. Since 2009, he has also served on the EQE Committee — the body responsible for assessing and admitting new candidate patent attorneys at the EPO.

Invalidity as a Defence to Infringement

Where a business receives a letter of claim alleging patent infringement, challenging the validity of the patent is often the most effective response. A patent that is successfully revoked removes the claimant’s entire cause of action — no infringement can be found if there is no valid patent.

We routinely advise defendants in infringement disputes on the strength of their validity arguments at an early stage. A well-founded invalidity counterclaim can change the dynamics of litigation significantly, often prompting settlement or withdrawal of the claim.

Defending Your Patent Against a Revocation Challenge

If your patent is under attack — whether by way of a UKIPO application, a court counterclaim, or an EPO opposition — prompt and well-prepared expert advice is essential. The burden of proof in revocation proceedings is on the party challenging validity, but a patentee who fails to engage robustly risks losing rights that may have taken years and significant investment to obtain.

Freeman Harris acts for patentees defending their patents against revocation and invalidity challenges. We work alongside David Sant’s prosecution expertise to ensure that any amendments proposed during contested proceedings are both allowable and effective in preserving meaningful protection.

Why Freeman Harris?

Freeman Harris is a London solicitors’ firm specialising in intellectual property. Unlike many firms that offer IP as an ancillary service, our patent team combines deep legal expertise with genuine technical and institutional knowledge of how patents are granted and challenged.

David Sant is triple-qualified: as a Solicitor-Advocate (with rights of audience before all civil courts of England and Wales), as a Solicitor in Ireland, and as a European Patent Attorney before the EPO. His technical expertise spans the physical sciences, with particular depth in mobile telephony, standard-essential patents (SEPs), FRAND issues, software patents, communications, navigation, optics, interferometry and horology. He has appeared in patent proceedings before the High Court in London and conducted oppositions directly before the EPO, and has served since 2009 on the EQE Committee at the EPO — the body that assesses and admits new European Patent Attorneys.

We advise businesses across technology, telecoms, engineering, and the physical sciences, as well as individual inventors, universities, and start-ups seeking to protect or challenge patent rights.

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