The importance of confidentiality was reinforced in a recent Patent Office decision concerning prior art and a disclosure over a home made device which made obvious a patent for an electric lawnmower with an integral cable spool.
The inventor had shown his device to four individuals namely two employees who had helped him develop the device and two neighbours. One employee had signed an NDA, it was therefore considered to be confidential. One of the neighbours had assisted with the invention but was aware of the need to keep the invention secret and it was therefore likely that this neighbour was under an implied obligation of confidence. However and this is the crucial point the other neighbour saw the device after the application had been filed, therefore the invention had been made public and was prior art and could be fatal to the patent application. The lesson from this is to ensure that all inventors enter in to confidentiality agreements with all persons it discloses its ideas and inventions to. Make sure its in writing and expressly sets out what is being disclosed.