Home > Insights > UKIPO acknowledges the possibility of a Formstein defence
14 January, 2022

Ever since the Supreme Court shook up the patent landscape in the UK with their decision in Actavis v Eli Lilly there has been an open question regarding how the newly enlarged patent scope which encompasses equivalents interacted with validity and third-party certainty.

Prior to Actavis, the Gillette defence or Gillette principle was often referred to. While not strictly a defence to patent infringement, the Gillette principle was essentially that the grant of a patent should not prevent a person from carrying out acts which they were carrying out prior to the priority date of the patent. That is, if a person was selling a product prior to the priority date of the patent, sale of the same product cannot be considered to infringe the claims of the patent. If the product did infringe the claims of the patent then the patent must be invalid since the product itself would be prior art. Thus, if an alleged infringement is not novel or is an obvious modification of this earlier product then the defendant would have a strong defence against any patent infringement argument.

With the Actavis decision, a new question was raised in that what if the defendant’s device was not novel or was obvious over something that would be considered an equivalent under the Actavis test, but not under a normal construction. In such a case, would the Gillette defence still apply?

In jurisdictions which have had doctrine of equivalents for longer than the UK, such a question has already been addressed. The most well-known decision is the Formstein decision in Germany, which leads to the so-called Formstein defence. The Formstein defence essentially extends the Gillette defence to encompass the doctrine of equivalents. If a third-party device is covered under the doctrine of equivalents, but is not novel or is obvious over prior art that predated the priority date of the patent, then the scope of the patent is limited to not include this device. This therefore avoids the question of a patent being invalid based upon the scope of any potential equivalents.

This question has not been decided upon in a UK case yet, but has been referred to in obiter in a number of cases such as Technetix v Teleste and Facebook v Voxer. In each of these cases, the obiter remarks referred to the possibility of a Formstein defence and generally opined on it in a favourable manner.

As each of the cases only discussed the presence or not of a Formstein defense in obiter remarks, there is no binding decision to refer to. Indeed, it is likely that a Supreme Court decision will ultimately be necessary to confirm the existence or otherwise of a UK Formstein defence. However, interestingly the UK Intellectual Property Office’s Manual of Patent Practice has been amended to quote the above-noted cases and discuss the possibility that such a defence may exist in Section 125.17.8. The Manual is clear that the cases simply suggest that the Formstein defence may exist, but its introduction is an indication of the direction that UK law appears to be heading in. Certainly, it appears to be a significant step that the UKIPO deems the possibility of such a defence worthy of mention in the Manual.

The Manual of Patent Practice is not binding upon UK Courts. However, the UKIPO does offer an Opinions service in relation to validity or infringement by which they provide an independent assessment. If the outcome of such an Opinion turned upon whether there is a Formstein defence or not it would be interesting to see how this was handled given the new reference in the Manual.

Interested parties will continue to watch for the latest developments in this aspect of UK patent law and we await the first case in which the Formstein defence is truly tested in the UK.