Background
The scope of protection afforded by a patent is defined by its claims, those strangely-worded single-sentence statements found at the back of your patent. If a competitor makes or does something which falls within the scope of at least one of your claims, then you can use your patent to stop them from doing so. Until recently, the scope of your patent in the UK was defined by what the claims said i.e. the literal scope of the claims. Claims were to be construed purposively (i.e. to give the claim purpose) which could sometimes stretch the scope of protection of the claims a little past their literal meaning, but such stretching would be limited. If your patent claims included features which were unduly limiting or not essential, then tough.
In some other countries, the scope of a patent hasn't been limited to the literal language of the claims. Those claims also protect features which are equivalent to those listed in the claims under a legal construct often known as the "doctrine of equivalents" or "doctrine of equivalence". For example, if a patent claim referred to a "helical spring", then under the doctrine of equivalents, a leaf spring may also be covered by the claim because the leaf spring is equivalent to a helical spring. In most countries there are well-defined rules determining how far the claim language stretches under this doctrine of equivalents.
The moving goalpost (or making the goals wider)
In 2017, the UK Supreme Court issued a decision which means that there is now a doctrine of equivalents in the UK, and the scope of UK patents is now potentially significantly broader. In the Supreme Court case, the claims of the patent were limited to a sodium salt of a pharmaceutical. Reference to the sodium salt was added in order to get a patent granted. The Supreme Court considered whether a potassium salt of the same pharmaceutical would infringe the claim referring to the sodium salt. There is no doubt that the potassium salt does not fall within the literal wording of the claims.
Furthermore, it is highly likely that under the old law, the scope of the claims would not have stretched to cover the potassium salt and there would have been no infringement. The Supreme Court decided that the potassium salt would infringe the claim of the patent because (i) the potassium salt worked in the same way as the sodium salt, (ii) it would have been obvious to someone working in the technical field of pharmaceuticals that the potassium salt worked in the same way as the sodium salt and (iii) someone reading the patent would have concluded that the patentee did not intend that strict compliance with the literal wording of the claims to be essential.
So what?
While this decision may not seem too bad, and may even appear to be sensible to some degree, in answering point (i) above, the Supreme Court rather worryingly referred to assessing whether the potassium salt works in the same way as the sodium salt, having regard to the inventive concept of the patent (i.e. consider the clever idea disclosed in the patent). There is significant concern that this assessment based on the inventive concept, coupled with point (iii) above, will mean that courts will have to stretch the claims to cover what the patent ought to have covered, having scant regard to the wording of the claims.
This is best illustrated with reference to a couple of later examples from lower courts which are essentially bound to follow the Supreme Court's earlier decision.
In each case, the possible infringement did not fall within the literal scope of the claims because there was a variant feature which differed from the feature of the claim. However, in each case, the variant feature was found to fall within the scope of the claims because: (i) the variant feature worked in the same way as the claim feature, the claim feature having nothing to do with the clever idea behind the patent, (ii) this [point (i)] would have been obvious and (iii) there was nothing in the patent which stated or alluded to the claim feature being essential.
Practical implications for clients
It is clear that patents in the UK are broader than before. This has potentially significant implications for clients in that their patents will possibly be broader than before, but so will those of their competitors.
Clients may wish to consider asking their patent attorneys to revisit old freedom to operate opinions to see if there are any new risks, but this should only be done if clients are prepared to act on any new adverse infringement opinions. Clients may wish to consider looking afresh at competitors' activities to see if they can now be stopped with the potentially broader protection afforded to patents in the UK.
UK courts are issuing new decisions all the time and we anticipate that the law will develop over the next few years. In the meantime, your patent attorney will continue to write patent applications which provide you with the broadest protection possible, but do not be surprised if your patent attorney cannot give you a clear an answer as you would have liked in relation to whether patents in the UK are infringed.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
