A UK applicant can combine national, European and PCT routes, but the correct outbound strategy depends on target markets, the 12-month priority window and whether the invention falls within the security-sensitive categories governed by section 23 of the Patents Act 1977.
Outbound patent filing is a sequencing problem. The first filing, local security or foreign-filing restrictions, priority date, PCT/direct route, international search and target-country economics should be resolved together rather than as disconnected formalities.
| Starting position | Key decision | Practical route |
| Europe is the dominant target | Compare direct EPC route with PCT-to-EPO | Potentially earlier European prosecution vs PCT deferral |
| Many global markets are still under evaluation | PCT often preserves optionality | Defer most national/regional costs |
| Only a few foreign countries are certain | Direct Paris filings may be efficient | Avoid unnecessary international-phase layer |
| Security-sensitive subject matter | Check section 23 before foreign filing | UK first filing + six weeks or written authority as applicable |
| UKIPO as PCT Receiving Office | Use WIPO ePCT under current 2026 workflow | Coordinate with priority and security review |
UKIPO guidance makes clear that section 23 restrictions concern specified subject matter involving military technology, national security or public safety. It should not be presented as a general domestic-first-filing rule for every UK resident.
Where the statutory security condition applies, a UK resident generally cannot file abroad without written authority unless the same invention was filed at the UKIPO at least six weeks earlier and no section 22 directions remain in force.
A UK first filing can support a PCT filing within the priority year. The PCT can defer large country-by-country cost while providing an international search and Written Opinion.
Where Europe is a central commercial market, a direct European patent application can be compared with a PCT application that later enters the European regional phase. The better route depends on timing, geography and the value of deferral.
From 1 January 2026, PCT applications using the UKIPO as Receiving Office are filed digitally through WIPO ePCT. UKIPO has stated that its new patent service does not itself include PCT submission.
UKIPO’s 2026 transition guidance lists filing through ePCT with UKIPO as receiving office, direct filing with WIPO, and direct filing with the EPO among the available international filing paths.
UKIPO’s current filing-abroad factsheet states that a foreign application claiming priority from the UK application should normally be filed within 12 months from the earliest relevant UK filing date.
If the applicant expects US, EPO, Asian and other filings, the initial disclosure should support claim formats and fallback positions that can survive different eligibility, clarity and amendment standards.
The PCT search and Written Opinion can inform whether to amend under Article 19, request Chapter II examination or reserve objections for national/regional phase.
European coverage, the US, China, Japan, South Korea, Singapore, Australia and other markets should be chosen because of products, competitors, manufacturing, licensing or enforcement value rather than a generic country list.
The Patent Cooperation Treaty route can centralize the initial international filing and provide an International Search Report and Written Opinion before most national or regional phase costs arise. It does not create a single worldwide patent. The applicant still needs to choose the national and regional systems in which protection will be pursued. The site's National Phase guide, Where to File framework, international patent cost guide and timeline guide should therefore be read as part of the same decision.
The international search is not only a procedural milestone. The ISR and Written Opinion can expose novelty, inventive-step, clarity or support issues before large national-phase expenditure. Applicants can compare PCT Written Opinion response options, including Article 19 amendments and Chapter II work where appropriate, and later use the site's Office Action Response resources when national or regional examiners raise jurisdiction-specific objections.
International strategy begins before the PCT filing. The specification should preserve technical detail, alternatives, fallback positions and claim support that can be used across different patentability and amendment systems. Technology-specific planning is available through the technology filing hub. A filing route that delays cost but starts from a weak disclosure can still produce expensive prosecution problems later.
Patent rules, security restrictions, PCT fees, competent Authorities and national-phase procedures can change. Verify the current official materials before acting on a specific application.
International filing decisions are easier to defend when priority, disclosure, PCT strategy, search results, national-phase cost and later prosecution are treated as one connected patent lifecycle.
rd (at) patentbusinesslawyer (dot) com
