UK patent case law: The rules on equivalence

It is a little over a year since the UK Supreme Court’s Actavis v Eli Lilly decision was handed down by Lord Neuberger, in July 2017. Readers will recall that this redefined how the scope of a patent in the UK is determined. For the first time UK law embraced a ‘doctrine of equivalents’, where variants that are not covered by the actual wording of a patent claim can nevertheless be an infringement.

The many questions thrown up by this decision are now being addressed by the courts, as they gradually negotiate the challenges of applying Neuberger’s new test which, for brevity, I will paraphrase as: