The Unified Patent Court (UPC) has introduced new dynamics to European patent litigation. For businesses operating in Europe, the risk of being hit with a pan-European preliminary injunction – even without prior notice- is real. Protective letters are a practical tool to reduce this risk and ensure your side of the story is heard before any urgent measures are granted.
What is a protective letter?
A protective letter is a pre-emptive submission to the UPC. It sets out your arguments, such as non-infringement or invalidity, before any request for a preliminary injunction is made. If a competitor applies for an injunction, the court will already have your position on file, increasing the chance that it will not grant the injunction, or at least not without a hearing.
Why does it matter?
The UPC moves quickly. Decisions on preliminary injunctions can be made within weeks, and a single injunction can block sales in 17+ EU countries. In many cases, the first notice a company receives is the injunction itself. A protective letter helps ensure you are not caught off guard.
Proven effectiveness
The protective letter system is not new—it has already proven effective in German courts. At Withers & Rogers, we have successfully used protective letters to shield clients from serious business disruption. This experience translates directly to the UPC, where similar risks now apply across a much wider territory.
What to do next?
If you are concerned about potential UPC risks, Withers & Rogers can help you file a protective letter quickly and effectively. Even if you think it might be too late, we encourage you to contact us – acting fast can make all the difference. Our team is ready to respond rapidly and protect your business from sudden disruption.
Practical steps
- Identify products and business areas exposed to European patents, especially where litigation is likely.
- At the first sign of trouble, such as concerning results of FTO, warning letters or aggressive communication, consider filing a protective letter.
- Protective letters are valid for six months; renew if the risk persists.
- Ensure your teams know to escalate legal notices immediately – UPC deadlines are tight.
Ute Pfaller
UPC Group
This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.
© Withers & Rogers LLP April 2026
