While some politicians seem to get away with making sometimes promises during an election campaign, with little prospect of fulfilling them all subsequently, patent applicants need to be much more careful. Promises made in the patent specification and not met can be a ground for invalidity.

One of several requirements for patentability under Australian patent law is that the invention as claimed is useful. This is sometimes referred to as the "utility" requirement. The basic principles of lack of utility (inutility) can be traced back to earlier English patent law and inutility has been a statutory ground of invalidity in Australian patent law for many decades. Although the ground of inutilit) is often pleaded in revocation proceedings in the courts, it is comparatively rare for invalidity to be found on that ground. In those comparatively few cases where an inutility attack has succeeded, the failure to provide utility has usually resulted from the inability for the invention as claimed to fulfill an expressed objective of the invention. In a recent decision of the Federal Court Ronneby Road Pty Ltd v ESCO Corporation [2016] FCA 588 "inutility" was found in a circumstance where the patent specification indicated several advantages which would be achieved by the invention. The court found that only some of those advantages were, on the evidence, achieved and invalidity was found on that basis.

The invention concerned replacement wear members for excavating buckets of the type typically used on mine sites and the like. In effect, these wear members form teeth at the edge of the bucket and cut into the ground. They are subject to harsh conditions and heavy loading and require periodic replacement.

The inutility ground of invalidity in this case was based upon a paragraph within the summary of the invention which said that the invention would provide advantages of enhanced stability, strength, durability, penetration, safety, and ease of replacement of the wear members. The assessment of utility was in relation to the invention as claimed and the passage referred to was construed as meaning that all six of the advantages would be achieved. The evidence accepted by the court was that the invention defined in only some of the claims achieved some but not all of the advantages, and inutility was found on that basis. Although not clear from the decision, one presumes that those advantages were all achieved by preferred embodiments of the invention as described in detail in the specification. In reaching this conclusion the court followed an earlier authority of the NSW Supreme Court in which only some of a larger number of promised advantages were attained.

Notwithstanding the finding of invalidity for inutility this defectit is nevertheless correctable by amendment. The amendments needed would be within the scope of amendments permitted in the patents legislation and a simple change to the paragraph in question would likely achieve that. Although allowance of amendments at this stage is discretionary, it is evident from a subsequent part of the decision that the court was prepared to allow or to consider amendment in this case. However, this does not mean that corrective amendment will always be permitted where a court finds invalidity on this ground. This is a sharp message to all of those drafting patent specifications when making promises, however expressed, as to the advantages and benefits of an invention.