Relevance of protective letters
Regulation of protective letters

Protective letters have been a useful and effective tool imported to Spain from the regulations of other European countries. The regulation of protective letters first appeared in Spain in the Patent Act, which came into force on 1 April 2017. However, before the implementation of the Patent Act, some specialised patent courts(1) admitted the presentation of such writs by companies that expected to be sued in ex parte preliminary injunction proceedings. Since then, protective letters have become a common tool used by potential defendants in patent matters.

Relevance of protective letters

Protective letters have a special relevance in the context of some fairs, such as the Mobile World Congress (MWC), the world's largest and most important event in the mobile communications industry, which has been held in Barcelona in recent years.(2)

In order to avoid possible conflicts that could arise between the companies participating in the event, the Panel of Judges of the Commercial Courts of Barcelona, for the seventh consecutive year, together with the Panel of Judges of the Commercial Courts of Alicante (European Union Trademark Court), for the third time, agreed to adopt a specific protocol of guard service and rapid action. The protocol contained effective measures to protect technological innovations and patents, industrial designs, trademarks, copyrights and, in defence of competition law, unfair competition and unlawful advertising acts in relation to products and materials on display at the MWC. Among these actions, the protocol established that the admission of protective letters would be resolved on the same day as the presentation of such letters. This admission and immediate resolution of protective letters aimed to avoid the adoption of ex parte preliminary injunctions, which would allow the defendant to put forward their arguments and express their willingness to appear at the court immediately if any requests for ex parte interim injunctions were filed.

Regulation of protective letters

From the start, there was a difference between the Spanish regulation of protective letters and the regulations of other European countries, due to the fact that the Spanish courts informed the patentee of the existence of the open proceedings in relation to its patent. However, the courts did not allow for the possibility of accessing the protective letter until the patentee decided to initiate preliminary injunction proceedings.

However, in recent years, the Barcelona patent courts have taken another step in this matter, allowing patentees to appear in proceedings initiated by the potential defendant via the submission of a protective letter and, therefore, to gain access to the protective letter before filing the preliminary injunction motion.

On 27 May 2021 Barcelona Commercial Court 1 of issued an order consolidating the most updated case law established by the Barcelona patent courts. Such case law established that although the patent courts had previously expressed their reservations about potentially reversing the natural order of the positions in the civil process, allowing a future plaintiff (ie, a patentee) to gain access in advance to the defence arguments of the future defendant, after a more detailed study they found that the impact of permitting such access is not significant, for the following reasons:

  • The future defendant has the possibility of modifying their allegations and evidence in a potential preliminary injunction hearing. The preclusion rule does not apply in this case and, moreover, the future defendant is not bound by the arguments set out in the protective letter.
  • A patentee that opts to appear at proceedings initiated by a protective letter in order to find out the content of such letter – with the aim of adjusting the arguments of its urgent preliminary injunction motion – could damage its position in relation to the urgency required in this kind of preliminary injunction.
  • The order reminds defendants that when a potential defendant asks for an anticipated defence of its rights, it must assume the consequences of the application of an imperative procedural system in which everything will be served to the other party.


As this seems to be the current position of the Barcelona patent courts in relation to protective letters, it will be interesting to see how patentees act in a situation in which they know that there is a protective letter in relation to one of their patents: will they try to find out the arguments despite potentially weakening their position, or will they ignore the content of the protective letter in order to be able to prove the extreme urgency needed in these cases?

Bearing in mind the above, it will also be interesting to see whether this new situation causes the potential defendant to file shorter and weaker protective letters so as not to give any advantage to the patentee, even while knowing that hiding arguments and evidence can make the court not uphold the petition for a hearing in the event that the patentee files an ex parte preliminary injunction motion.

For further information on this topic please contact Ana-Laura Morales at Grau & Angulo by telephone (+34 93 202 34 56) or email ([email protected]). The Grau & Angulo website can be accessed at


(1) There was a dispute in relation to the admissibility of protective letters before the current Patent Act came into force, due to the fact that, unlike the Barcelona patent courts, some Madrid patent courts did not admit them.

(2) The most recent edition of the Mobile World Congress was held in Barcelona from June 28 to July 1 2021.