Under the European Patent Convention (the EPC), a patent applicant discloses a novel invention if what is taught in the application does not form part of the state of the art. The state of the art includes:
1. Everything made available to the public, before the date of filing the European
patent application in question, by means of:
a. Written description
b. Oral description
c. Use or
d. in any other way.
The concept of prior use in patent law is therefore most often encountered where a patent application is alleged to be invalid because it is not novel or inventive as the invention claimed was available prior to the filing date as an embodiment was available to the public.
In Lux Traffic Controls Ltd v Pike Signals Ltd and Faronwise Ltd, Aldous J stated that:
There is a difference between circumstances where the public have an article in their possession to handle, measure and test and where they can only look at it. What is made available to the public will often differ in the circumstances. In the latter case it could be nothing material whereas in the former the public would have had the opportunity of a complete examination
In other terms, novelty is destroyed by prior use of a product if analysis of the product using available techniques shows the skilled person that it falls within the scope of the claims of the subsequent application.