The Patent You Can Never Publish: How The Government's Secret Powers Can Trap Your Invention.

Addressing the legal framework governing U.K. Government powers over privately developed defense technology.

Introduction

Imagine filing a patent application for a technology your company has spent years and significant capital developing—only to receive a direction from the U.K. Intellectual Property Office telling you that your invention must be kept secret. You can't publish it. You can't communicate it to investors, customers, or collaborators. You can't file abroad. And if you try to withdraw the application and walk away to escape those restrictions, you will find that you can't, the secrecy order remains in force regardless. Walking away solves nothing.

This is not a hypothetical. Under section 22 of the Patents Act 1977 (PA 1977), the Comptroller-General of Patents has the power to issue a secrecy direction that does precisely this—and breach is a criminal offence. This article explains how the regime works, how common it is, and what the consequences are for your business.

A secrecy direction – the process

All patent applications filed with the U.K. Intellectual Property Office (IPO) are passed through an automated screening system operated by the IPO's Security Section within days of filing. The system checks each application against a defined set of keywords, technology categories, and performance or functional parameters supplied by the Ministry of Defence (MOD) and other government departments. Applications that match those criteria are flagged for potential referral to the MOD, those that don’t match proceed normally. Every application is therefore processed through the system—but it is the match against the defined criteria, not the act of filing itself, that triggers the security review.

The statutory test under section 22 PA 1977 is whether publication might be prejudicial to national security or to the safety of the public. “National security” in this context is a broad concept encompassing military and defense capability, intelligence and signals intelligence technology, and other threats to the state. In practice, defense technology is the primary category at which the regime is directed—the MOD supplies the keyword lists and makes the substantive assessment—but the power is not limited to defense technology in the narrow sense: Cryptographic technology used in intelligence applications and certain dual-use technologies with public safety implications fall equally within scope.

The high-level categories of technology for which the system screens are publicly described in outline, but the detailed keywords, subcategories, and specific performance or functional parameters applied by the system are not published and are themselves treated as sensitive. Those parameters are likely to mirror, or cross-reference, the threshold-based criteria used in the U.K. Military List and Strategic Export Control Lists—meaning that an invention may be flagged not simply because it falls within a broad technology category, but because the specific performance characteristics disclosed in the application (accuracy figures, frequency ranges, power outputs, or similar) meet or exceed a defined sensitivity threshold. For companies operating in dual-use fields, the level of specificity with which such characteristics are described in the application is therefore not a matter of indifference. Pre-filing advice from a practitioner familiar with both the patent system and the export control framework is advisable—though it should be emphasised that deliberately incomplete or evasive drafting raises its own problems of validity and enforceability and is not a reliable strategy for avoiding the screening process.

Where it appears to the Comptroller that the publication or communication of an invention might be prejudicial to national security or public safety, the Comptroller may give directions prohibiting or restricting the publication or communication of information about the invention. The legal instrument used is called a secrecy direction.

The decision must be made before publication at 18 months. Because the consequences of inadvertent publication of a sensitive invention are serious, the IPO's safe default is to err on the side of caution. If a keyword or drawing looks as though it might relate to a sensitive area—even indirectly—the Comptroller issues a precautionary direction, which stops publication and allows the MOD or relevant department to investigate in more detail. Most initial secrecy directions are therefore precautionary: they don’t mean the invention is a top-secret weapon design; they mean that more time is needed to check whether it really is sensitive.

The secrecy direction is reviewed within nine months of the filing date and at least annually thereafter (section 22(5)(c) PA 1977). This mandatory annual cycle is significant; unless the relevant government department actively re-certifies the need for continued secrecy each year, the direction lapses.

Withdrawal or abandonment of the patent application does not discharge the secrecy direction. The direction must be formally revoked by the Comptroller. This makes filing a patent application a potential one-way door. Once you trigger the power, simply walking away from your application does not undo it.

The prevalence of secrecy directions

Secrecy directions are rare in aggregate, but their incidence is higher than most practitioners assume—and the stock of active directions has been growing significantly in recent years.

According to the IPO's Facts and Figures 2024 dataset (published in June 2025), 61 secrecy directions were issued in 2024 alone: 51 to U.K. origin applicants and 10 to applicants from outside the U.K. In an estate of approximately 20,000 applications handled by the U.K. IPO each year, 61 directions represent about 0.3% of total filing volume. Viewed from another angle, however, the IPO is issuing a secrecy direction on average roughly once a week—a frequency that may surprise companies and advisers who regard the regime as a theoretical curiosity.

The non-U.K. figure—roughly one in six of all directions—reflects the U.K. IPO's role as a receiving office for European patent applications and PCT international applications, as confirmed by the IPO's own statistical footnotes. It also reflects the U.K.'s participation in intelligence-sharing arrangements with Five Eyes partner nations, under which applications from allied states may be routed to the U.K. filing system in circumstances where security screening in the U.K. is considered appropriate. The Five Eyes mechanism is the primary explanation for why a material proportion of secrecy directions fall on applicants who did not themselves set out to file a U.K. national application.

The historical trend data, drawn from the same primary source, tells a more striking story than the annual headline figure. Between 2000 and 2024, a total of 1,755 secrecy directions were issued by the IPO. Of the directions attributable to applications filed since 2000, 1,151 remain in force—a substantial and growing stock. The reason that stock is growing is the sharp collapse in the rate at which directions are being released. Between 2007 and 2013, annual declassification rates were consistently high: 184 releases in 2007, 186 in 2013, and over 75 in several other years. The pattern reflected the cautious approach to initial screening: the MOD would complete its assessment and, in the large majority of cases, confirm that the invention did not pose a continuing security risk, at which point the direction was revoked, typically within six to eighteen months of issue.

That release rate has collapsed almost entirely since 2016. In the years 2018 to 2024, the annual number of directions released was six, three, four, five, ten, fifteen, and seven respectively—a fraction of the 34 to 66 new directions being issued each year over the same period. In 2024, 61 new directions were issued, and only seven were released. The regime is now issuing roughly nine times as many new directions each year as it is releasing. The active stock is growing rapidly.

The categories of invention most commonly subject to enduring directions are: certain nuclear weapons engineering and fissile materials handling, cryptographic algorithms used by GCHQ, certain sensor or guidance systems with ongoing classified capability, and technologies within current deterrent or SIGINT systems. The defense industry accounts for the overwhelming majority of all applications that receive directions: in 2024, 48 of the 61 directions (79%) were issued to defense industry applicants, with private inventors accounting for just one. For companies outside the defense supply chain, the risk remains remote. For those within it, it is a live and growing operational consideration.

The effect of a secrecy direction

The consequences of a secrecy direction are considerably more far-reaching than simply delaying publication of your patent application.

Disclosure restrictions

A direction under section 22(1) or (2) PA 1977 prohibits or restricts the publication or communication of information about the invention and its communication to any specified person or class of persons. This is not simply an order that the patent application should not proceed to publication. It is an affirmative order that the applicant must keep secret its own technology. This is an extraordinary statutory power, and amounts to a highly unusual interference with private property. We consider the constitutional and human rights aspects of this power in the last article in our series.

No granted patent

While the direction is in force, the patent application is handled by the Security Section examiner and, although it may proceed through examination to a stage at which it would be in order for grant, it is neither granted, published, nor communicated. Once the direction is revoked, the Comptroller has discretion to allow extended time limits in connection with the application (section 22(5)(e) PA 1977).

There are controlled exceptions: the applicant may apply for the Comptroller's consent to communicate the invention to specified persons, such as internal R&D staff, potential licensees, or subcontractors. All such consents are narrowly drawn, and the default position is nondisclosure.

Foreign filings

Once a secrecy direction is in force, foreign patent applications are generally prohibited unless the Comptroller gives written consent (section 23(1) PA 1977). Such consent, where granted, is typically limited to jurisdictions with equivalent national-security patent screening regimes—principally the Five Eyes allies and a limited number of close NATO partners. Separately, and irrespective of any secrecy direction, section 23(1A) PA 1977 requires any U.K. resident to file first with the U.K. IPO—and to wait at least six weeks—before making any application abroad if the invention relates to military technology or if publication could be prejudicial to national security or public safety.

Criminal liability

It is a criminal offence to fail to comply with a secrecy direction or with the rules on foreign filing under section 23 PA 1977. Breach of a direction under section 22(6) makes any person who fails to comply liable on summary conviction to imprisonment for a term not exceeding six months or to a fine, or to both; and on conviction on indictment to imprisonment for a term not exceeding two years or to a fine, or to both. There is additionally no right of appeal against the Comptroller's decision to give a direction: section 97(1)(c) PA 1977 expressly excludes such decisions from the right of appeal to the Patents Court.

Compensation

Where a secrecy direction has been in force and has caused hardship, the Secretary of State may, with the consent of the Treasury, pay compensation. This only applies if, while the prohibition was in force, the invention was used for Crown services (section 22(7)(a)).

In practice, compensation is thought to be rare—directions tend not to last long enough to cause significant loss, and the process is entirely discretionary. There are no reported judicial decisions compelling payment. There is no statutory right of appeal against the Secretary of State's refusal to pay, nor against the amount of compensation awarded.

Key takeaways

• Filing a U.K. patent application is a trigger event for the IPO's security screening process and secrecy order jurisdiction. Companies in the defense technology space should assess their exposure before filing.

• Secrecy directions are rare—approximately 0.3% of total annual filings with the U.K. IPO—but their incidence is consistent: the IPO issues roughly one direction per week. For defense industry applicants specifically, the risk is considerably higher than the aggregate statistic suggests.

• The stock of active directions has grown substantially in recent years, driven by a near-complete collapse in the rate of declassification since 2016. In 2024, 61 new directions were issued against only seven releases. The regime is accumulating active directions at pace.

• A direction can restrict publication, communication, commercialization, fundraising, and foreign filing. The impact on a growth-stage company can be severe.

• Withdrawing the patent application will not remove the direction. There is no right of appeal against the decision to issue one.

• Breach of a direction is a criminal offence. On conviction on indictment, the maximum sentence is two years' imprisonment. If loss is caused, compensation is available but wholly discretionary, and no reported case has compelled payment.

Conclusion

The IPO security screening process means that filing a U.K. patent application in the defense technology space is a trigger event that companies should not approach without careful thought. Secrecy orders are rare, and most are revoked relatively quickly, but if a direction is made it can restrict publication, communication, commercialization, and foreign filing in ways that can materially damage a growth-stage company—and compensation is at best an uncertain remedy. Because withdrawing the patent application will not remove the secrecy order, filing is a one-way door.

The data from the IPO's most recent published dataset makes clear that the regime is not merely a theoretical risk; over 1,150 directions arising from applications filed since 2000 remain in force, and the stock is growing. In 2024, only seven directions were released against 61 new issuances—the starkest illustration of a regime whose active inventory is expanding year on year.

Companies operating in the defense technology space should take legal advice before filing to understand their exposure and should prepare contingency plans in case a direction is imposed. In our next article, we consider the particular challenges facing U.K.-based defense software companies whose primary commercial objective is patent protection in the U.S. Founders and companies who are tempted to protect their technology as a trade secret—in order to avoid triggering the secrecy order regime under section 22—should not assume that doing so takes them outside the scope of government control. Our subsequent articles address the extent to which the U.K. government can impose security controls on unpatented, privately-funded technology.