What is “Inventive Step”?

“Inventive step” (as it is known in the UK, Germany and the European Patent Convention), or non-obviousness (predominantly used in the United States), is another patentability requirement which needs to be fulfilled.  If what is claimed has novelty, but the novelty was not the result of any inventive activity, then the patent is obvious and therefore not inventive.  Arguments on the obviousness of the claims must be based entirely on prior art and not on any knowledge of the present invention.  An invention can only be classed as containing inventive step if it is not obvious to a person skilled in the art.  The UK IPO has published a handbook on the inventive step requirements for a patent and the link to this is given here.