Richard Meade QCand Andrew Lykiardopoulos acted for Kennametal in its successful defence of patent infringement proceedings brought by the Sandvik. The dispute concerned alumina coatings for cutting tools and corresponding litigation is ongoing in the USA and Germany. Arnold J held that the patent was invalid for insufficiency and that the claims alleged to be infringed were also invalid for obviousness. The judgment considers in some detail the law of sufficiency together with the law on obviousness for lack of technical effect