In this decision, the UK Court of Appeal confirmed that obviousness must be assessed by reference to the invention as described and claimed by a patentee. In order to undertake that assessment, all the circumstances including, where appropriate, whether it was obvious to try a particular route with a reasonable or fair expectation of success, must be taken into account. What is a reasonable or fair expectation of success will again depend upon all the circumstances, and is fact dependent.
Sometimes, it may be appropriate to consider whether it is more or less self-evident that what is being tested ought to work. However, simply including something in a research project in the hope that something might turn up is unlikely to be enough. The Court rejected that a finding of obviousness can only be made where it is manifest that a test ought to work. Such a straightjacket upon the assessment of obviousness is not warranted by the statutory test and would, for example, preclude a finding of obviousness in a case where the results of an entirely routine test are unpredictable.