Patent infringement

Patent infringement


What amounts to infringement

A person infringes a patent for an invention if, while the patent is in force, they do any of the following things in the UK without the patent owner's consent:

  • Where the invention is a product, they make, dispose of, offer to dispose of, use or import the product or keep it, whether for disposal or otherwise
  • Where the invention is a process, they use the process or offer it for use in the UK when they know, or it is obvious to a reasonable person in the circumstances, that its use would be an infringement of the patent
  • Where the invention is a process, they dispose of, offer to dispose of, use or import any product obtained directly by means of that process or keep any such product, whether for disposal or otherwise

A person may also infringe if they supply (or offer to) a person not entitled to work the invention, with means relating to an essential element of it for putting it into effect in the UK. A person does not infringe unless they know, or it is obvious to a reasonable person in the circumstances, that those means are suitable and intended for putting the invention into effect in the UK. The supply must occur in the UK. For this purpose, the supply or offer of a staple commercial product is not an infringing act unless it is for the purpose of inducing the recipient to do an infringing act of the type described above.

An act which would otherwise constitute an infringement of a patent for an invention shall not do so if, amongst other things, it is done privately and for purposes which are not commercial or it is done for experimental purposes relating to the subject matter of the invention.

Remedies for infringement

The owner of a patent can take legal action against you and claim damages if you infringe their patent.

In proceedings for infringement of a patent before the court, the owner may claim an injunction (or, in Scotland, interdict) restraining infringement, an order to deliver up or destroy infringing articles, damages, an account of profits and a declaration (or, in Scotland, declarator) that the patent is valid and infringed. However, the court cannot both award damages and order an account of profits in respect of the same infringement.

If the owner and an alleged infringer agree to do so, they may refer the question of infringement to the Comptroller. The Comptroller is the Comptroller-General of Patents, Designs and Trade Marks; in practice, the responsibilities of that office are delegated to officers within the IPO. Unless he declines to do so, the Comptroller will determine whether the alleged infringer has in fact infringed the patent. However, the powers of the Comptroller are more limited than those of the court, and the owner can claim only damages in respect of the infringement and a declaration that the patent is valid and infringed.

There are certain situations where the remedies available are restricted. The court or the Comptroller cannot, for example, award damages or make an order for an account of profits against an innocent infringer. However, the onus is on the infringer to prove their own innocence, i.e. that at the date of the infringing act they were not aware, and had no reasonable grounds for supposing, that the patent (or published application for a patent) existed. The test concerns only ignorance of the existence of the patent and not failure to appreciate that an act committed by them might constitute an infringement. If the infringer had no actual knowledge, the existence of reasonable grounds must be judged in the light of all the circumstances at the time of the infringement; the test is objective.

The fact that a product is marked with wording to the effect that it is patented is not enough to establish that other persons should be aware of the patent, unless the patent number is quoted in the marking. It is an offence to dispose of for value a product marked with wording claiming that it is patented if the claim is false.

If a patent lapses due to non-payment of a renewal fee by the renewal date, but that fee together with an additional fee is paid by the end of the sixth month after that date, the patent is treated as if it had never lapsed. However, the court or Comptroller has discretion to refuse to award damages or to order an account of profits in respect of an infringing act committed in the intervening period.

How to avoid infringing

You can request a freedom-to-operate search from the IPO to find patents you might be at risk of infringing. It also has a database of patents that are currently not in force.

Response to infringement proceedings

There are two basic types of defence if someone claims you are infringing their patent:

  • You are not infringing - i.e. what you are doing does not infringe their patent claims
  • The patent is invalid - you can take legal action to challenge the validity of the patent. If you win, their patent may be cancelled (revoked).


The court or Comptroller may revoke a patent for an invention on the application of any person on any of the following grounds:

  • The invention is not a patentable invention
  • The patent was granted to a person who was not entitled to be granted that patent
  • The specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art
  • The matter disclosed in the specification of the patent extends beyond that disclosed in the application for the patent, as filed
  • The protection conferred by the patent has been extended by an amendment which should not have been allowed