If there is a patent granted only in another juristiction can they retrospectively apply for a patent if you manufacture something similar in a different juristiction?

Consider this time-line:

  • party A is granted a patent for DeviceA in juristicationA (e.g. the US)

  • party A manufactures and sells DeviceA in juristicationA (e.g. the US)

  • party B manufactures a similar device DeviceB in juristicationB (e.g. the UK)

    marking it "for sale in juristictionB only" or "not for sale in juristictionA"

    (as per example Can a product patented in US be manufactured in India)

Q If party A discovers DeviceB can they apply for a patent in juristictionB that would make party B's business infringe retrospectively?

partyB could be:

  • unaware of DeviceA or its patent in juristictionA
  • deliberating trying to fill the niche locally and make a copy of DeviceA available for customers in JuristictionB
  • creating a 'knock-off' product not caring that it might impact partyA's current or future international business.

Morally we might hope that the laws in juristictionB would try to protect partyB in cases 1 and 2 and try to protect partyA in case 3.

What is typically the legal stance in this case?

Would the question be significantly different if you considered "design rights" instead of "patentable mechanisms"?

2 Answers 2


There is nothing legally wrong with party B manufacturing a device anywhere where no one else has an issued patent, nor is there, in my opinion, anything morally wrong regardless of the three reasons you mention. A patent in the U.S. imposes no constraints on what can be made and sold in the U.K. Party A is free to decide to secure, or not secure, IP rights in which ever locations it deems important to its business plans.

Of course if party A did later get a U.K. patent, party B would need to stop making, selling, etc. anything that fell under the issued claims.

Can party A try to get a UK patent? Possibly - It would only be able to if it had initiated some appropriate action before the earlier of - (1) its patent application in the U.S. or anywhere else, was published, (2) it started selling anywhere in the world, or (3) it disclosed the invention anywhere in the world. An appropriate action would include filing a patent in any country that was part of the Paris Agreement as long as the UK (or EPO) application was filed within a year.

If those conditions were not met, party A can never file in the UK. The rules are the same in most places other than locations with some type of grace period.

Design rights, like the European Community Design Regulation, often provide for a grace period where the applicant's own disclosure can not be used against them. This would give party A a bigger window to decide if it wanted to secure its design rights than the window it has for its patent rights.

Retroactive infringement

There are scenarios where B makes a device that is fine in the U.K until A's patent issues. There is not retroactive infringement. As long as B stops making, selling, etc. as soon as the patent is issued they are not infringing.

In the U.S. there is rare possibility of retroactive royalty based on the infringer being put on notice of A's published application. It is called provisional rights in the U.S. - I don't know how common this is in other places.

Speed of perfecting rights

It is important for world-wide progress for implementers to know what an inventor will claim (and where) and what they will not. Learning from what others have done and copying it or build on it are a feature not a bug.

The publication of patents is to allow the world to benefit from what the inventor has done - within the constraints of any issued patent. That is what the inventor gives in a social contract with the rest of us in return for some limited exclusivity.

  • Fixed "unaware of DeviceA or its patent in juristictionB" -> "unaware of DeviceA or its patent in juristictionA" May 24, 2021 at 14:59
  • So basically with "Can party A try to get a UK patent?" you're saying if partyA doesn't almost immediately get a world-wide patent (i.e. in as many places as possible) other parties are free to copy them in other juristications? This seems problematic if there is any delay on partyA's part. e..g budgetry restrictions and focusing on home market first. May 24, 2021 at 15:06
  • This follow up is answered here: patents.stackexchange.com/a/19703/26017 May 24, 2021 at 15:13

I am not a lawyer so someone else might be more authoritative. However, I don't think this scenario is possible. If you file a US patent application, I believe you have up to one year to file equivalent foreign patent applications. Patent applications typically don't publish until 18 months after filing and a patent usually takes about 3 years to get granted. Thus if a US patent actual existed, you couldn't subsequent to that issuing file for an equivalent patent in a foreign jurisdiction as the US patent would represent prior art.

I don't know what the term "design rights" means. There are design patents, but those cover the ornamental design of functional objects which I don't think is relevant to the question being asked.

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