Comparing the UK National Phase and European Regional Phase of PCT Patent Applications

Comparing the UK National Phase and European Regional Phase of PCT Patent Applications


Applicants for International (PCT) patent applications who wish to obtain patent protection in the United Kingdom can do so through the UK national phase of the PCT or by filing a European regional phase, also called a Euro-PCT, application. Sometimes there is merit in filing both types of applications in parallel.

In this article we summarise the issues to consider when making this decision and we also comment on additional factors where patent protection is desired in several European countries as well as legal issues which can arise when an applicant obtains protection in the UK by two parallel routes. It is assumed that readers are already familiar with the PCT. If you are not, then we provide an introduction here.

The most obvious difference between UK national phase and Euro-PCT applications is that UK applications cover only the United Kingdom whereas European patent applications can, on grant, be validated in any of 39 European Patent Organisation Member States, including the UK, and potentially also one extension state and five validation states if additional steps are taken. It is also possible to register a newly granted European patent as a Unitary patent.


The deadline to enter the UK national phase or European regional phase of the PCT is the same, 31 months from the earliest declared priority date although there are differences in the rules around entering the national/regional phase late. The UK national phase may be entered as of right, up to two months late, with a surcharge. The European regional phase may be entered late by requesting further processing, at considerable expense, up to two months from the date of notification of an official letter which is issued shortly after the normal deadline. Accordingly, the final deadline to enter the European regional phase as of right, with a late surcharge, is usually a little later than the final deadline for the UK.

The regular (unaccelerated) UK national phase is generally quicker than the European regional phase. A UK patent would usually be granted in 1 to 4 years from the date of UK national phase entry whereas 2 to 5 years would be more typical for a European application. The UK patent application process cannot become too extended due to the UK compliance period which determines that the UK application procedure should be complete by 4.5 years from the earliest declared priority date, or 1 year from the issuance of a first examination report, whichever is later. On the other hand, some European patent application procedures become very extended, with long gaps between examination reports and the possibility of oral proceedings or appeal proceedings. (It is possible to request a Hearing on a UK patent application that is at risk of refusal but this is fairly rare.)

If divisional applications are filed in the UK, they are examined quickly and do not greatly extend proceedings, but European divisional patent applications can occasionally lead to proceedings being very protracted. Of course, delay is not always a problem. Applicants with important inventions who wish to keep a divisional application pending for as long as possible to maximise their ability to respond to potential infringers or to make it difficult for third parties to determine the precise scope of protection they wish to achieve would be better with a European application.


There are substantial cost differences between a UK national phase and a Euro-PCT application. A UK national phase application might incur approximately one-third of the cost of a Euro-PCT to file. (An exception to this would be where the PCT application was filed in French or German and there was no intention to file in any other English language territory and so a UK application would incur a translation charge which could otherwise be avoided). The cost of responding to examination reports before the UK Intellectual Property Office and the European Patent Office is similar, although UK responses are sometimes simpler and there are fewer formal requirements to comply with in the UK (such as claim feature numbering). European patent applications have official grant and printing fees and a requirement to instruct claims translations into two languages, whereas UK applications do not.

Furthermore, renewal fees are payable annually during the European patent application procedure but only after grant in the UK. After grant, a European patent must be validated in the territories where it is to take effect and this can be expensive for countries requiring translations of the claims or the entire specification. If a European patent is registered as a Unitary patent, the upfront cost is relatively low but renewal fees become large - and a Unitary patent does not cover the UK. Accordingly, the UK national phase application procedure will frequently incur total costs which are in the range of a quarter to a half of the costs of a corresponding European regional phase application. However, a European patent can have a much greater geographical scope.

European regional phase applications, like regular European patent applications, incur substantial excess claims fees for each claim in excess of 15, although excess claims fees are not payable at the time of regional phase entry but later, at the end of a 6-month period during which it is also possible to amend the claims to reduce or avoid excess claims fees. UK national phase applications incur excess claims fees for each claim in excess of 25. These fees are much lower than for Europe (at the time of writing (February 2024), GBP 20 per claim in excess of 25 versus EUR 265 per claim in excess of 15, increasing from the 51st claim) but are due at the time of national phase entry and any amendments to reduce excess claims fees must be made at the time of national phase entry.

Influence of International Search and Examination

European regional phase applications derived from PCT applications which were searched, and optionally examined, in the international phase by the European Patent Office usually remain with the same examiner and the regional phase application process usually follows on seamlessy from the international phase. If the international searching authority was any other office then the European Patent Office implements a supplementary search phase before the application process continues.

The UK Intellectual Property Office carries out its own search and examination of national phase applications but starts from and often refers to the international preliminary examination report. Accordingly examination often starts from a similar position to the international prelimineary examination report but without the same level of integration and consistency.

Unity of Invention

UK patent rules are not as strict as European Patent Office rules when it comes to unity of invention. The European Patent Office usually allows only a single independent apparatus claim and a single independent method claim but the UK Intellectual Property Office does not have this requirement. Accordingly, it is sometimes possible to have more independent claims considered together in the UK national phase than in the European regional phase.

Other Formal Requirements

Although the underlying legal principles should be the same, the UK Intellectual Property Office is sometimes less strict than the European Patent Office when considering added subject matter. It is sometimes possible to make amendments in the UK that would not be accepted by the European Patent Office.

Patentability Differences

The UK and European Patent Offices apply slightly different tests for inventive step. Although the European Patent Office employs the so-called 'problem and solution' approach, UK patent law has a different approach usually based around the 4-step Windsurfing/Pozzoli test. There is a fundamental difference in the way in which cited documents should be combined, with the UK test requiring consideration of what is the common general knowledge of the person skilled in the art. As a result, it is sometimes easier to show an inventive step in the UK national phase than in the European regional phase.

Beyond the scope of this article, the UK Intellectual Property Office and European Patent Office do apply slightly different patentability standards in a number of fields, notably Computer-Implemented Inventions (especially Artifical Intelligence and User Interfaces).

Post-Grant Differences

In contrast to European regional phase applications, there is no opposition period for granted UK patents. Their validity may be challenged through the UK Intellectual Property Office or the Courts but there is no direct equivalent of the European patent opposition procedure.

Multiple European National Phase Applications

If there can be times to enter the UK national phase in addition to or instead of the European regional phase, this begs the question of whether there is a benefit in entering the national phase in several European countries in addition to or instead of the European regional phase. This is however an option that is only rarely applicable. Firstly, in order to enter the national phase in several European countries it would usually be necessary to have the PCT application translated into multiple languages, significantly increasing costs and losing one of the benefits of the European application process that only limited translation is required. Secondly, it is important to remember that it is not possible to enter the PCT national phase in some European countries, a list is provided here. For such countries, a European regional phase application is the only option. Still, there are some subtle differences in the protection afforded by the different routes, for example at the time of writing a Danish national phase application affords protection in the Faroe Islands but a Euro-PCT does not.

Double Patenting Issues

Where an applicant obtains both a UK patent and a European application that designates the UK and affords the same scope of protection, the UK application will be automatically revoked by the UK Intellectual Property Office to avoid third parties having to be concerned with two essentially identical patents. This only applies where the claims are substantially the same; if there are significant differences in the scope of the independent claims then this will not apply. This can be avoided by, for example, being careful to maintain some differences in the independent claims, by revoking the UK patent or, more simply, by withdrawing the UK designation of the European patent before grant. The same issue does apply in some, but only some, other European countries.


In short, although the European regional phase remains the most common route to obtaining patent protection in the UK through the PCT application procedure, there are merits in specific circumstances in filing UK national phase applications instead or in addition to European applications.

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