Patents are territorial rights, which means they can only be granted and enforced in the territory or territories in which they have been applied for.

A number of international agreements have been put in place with the aim of making things easier for applicants who need protection across multiple countries, such as the European Patent Convention (EPC) and the Patent Cooperation Treaty (PCT).

As a consequence, in certain countries there are multiple routes for obtaining patent protection and this can sometimes cause confusion among inventors and applicants!

What options are available in the UK?

In the UK, patent protection can be obtained via four main routes:

  1. A UK patent application filed at the UK Intellectual Property Office (UKIPO);
  2. A European Patent (EP) application filed at the European Patent Office (EPO) and designating the UK;
  3. An international Patent Application (what we call a “PCT”) filed, for example, at the World Intellectual Property Office and which enters the regional phase in Europe, i.e. matures into a European Patent as per the above point;
  4. An international Patent Application which enters the national phase in the UK, i.e. matures into a UK patent application.

Independent of which route is chosen, some additional rules apply, most notably:

  • Once a first filing is made, and assuming certain conditions are met, there is a 12-month priority window in which it is possible to file further application and claim priority from the first filing, which means backdating the subsequent application to the date of the first filing.
  • The patent will last 20 years from the date of the first filing (with very few exceptions).

However, there are some inherent differences among the three patent systems (UK, EP, PCT) which are worth keeping in mind when thinking of the right filing strategy.

UK patent application

Filing a UK patent application at the UKIPO is the simplest (and generally quickest!) way of obtaining patent protection in the UK.

Filing fees are much lower as compared to a European Patent or a PCT and if a search is requested at the time of filing, the UKIPO will generally deliver a search report within 6 months, which means the applicant can start building an informed opinion on the chances of the patent application proceeding to grant as early as 6 months from the date of filing.

European Patent Application

A European Patent application is a single application which covers many European countries (plus a few non-European). A list and a map showing all territories which can be covered by a European Patent are available on the EPO website.

Filing fees are higher than for a UK filing. If the search is requested at the time of filing the EPO will also typically deliver a report in 6 months which is as quickly as for a UK application and can be useful if the applicant wants to have an initial idea on chances of success.

European Patent applications are examined centrally at the EPO and once granted they mature into a single patent which can be validated in all contracting states.

Upon grant, some countries require a translation of the claims or of the whole application. However, no further examination is conducted at national level once the patent has been approved centrally by the EPO.

International Patent Application

The PCT is an international treaty with more than 150 Contracting States which makes it possible to obtain pending rights with a single “international” patent application instead of having to file separately in each country.

PCT applications are different from national filings and European patent applications because they do not mature into a granted patent. Unlike for a European patent where the contracting parties will just accept the examination carried out centrally at the EPO, PCT applications must enter the national phase in each territory of interest and go through prosecution at national level, with all the related fees and costs for professional services.

The main advantage of an international application is that they can remain in the so-called “international” phase for a long period of time (generally up to 30 months from the priority date) before having to enter the national phase. Therefore an applicant can have up to 30 months before having to make a decision as to which countries they want to get protection in and having to incur the bulk of the costs for prosecuting the application across multiple countries.

Both the EPO and the UK can be designated when entering the national phase from a PCT.

In practice

The filing fees for European patents and PCT are considerably higher than filing in the UK alone hence they are clearly not the best route to protection if the UK is the only country of interest.

However, when an applicant is unsure on where they may need protection, a common strategy is to file a first application in the UK and then after 12 month file a PCT application, with the PCT application claiming priority from the UK application. This way, the initial costs are minimized and the applicant can buy some time to identify key markets and decide where it is worth protecting the invention. Additionally, a UK search report received before the 12 month priority deadline can help inform strategy before filing the PCT application.

Of course, different Examiners (and laws) mean that a UK, EP or PCT application for the same invention may have different outcomes. The prosecution of a patent application is not always straightforward.  There are many caveats which means it is often not possible to predict how long and how expensive it will be to get a patent application through to grant. Furthermore, in some cases an applicant may decide to withdraw or abandon an application or may be unsuccessful in overcoming an Examiner’s objection.

In such scenarios, the existence of multiple alternative routes can sometimes act as a safety net. For example, an applicant may be able to re-enter the national phase in the UK from a PCT application after abandoning an initial UK application.


When it comes to patents, there are several filing strategies to consider. Each case is unique and there are many questions to consider when deciding what is the best route to protecting your invention.

If you are unsure on what is the best option for you, speak to your patent attorney! We are here to help you understand the different mechanisms and to ensure that your rights are safeguarded in the best way possible.


At Scintilla, we help innovative companies get a grip on their intellectual property. Our unique commercial approach combines registration of patents and trade marks with strategic input so that IP can be a springboard for business growth. If you would like to discuss your IP needs, do contact us or book a free initial consultation!