Court clarifies when a UK patent can be revoked for being ‘obvious’


Date: 19 June 2009

The courts have recently clarified the test for when an invention is 'obvious', so that a patent awarded to protect it can be revoked, so existing patent owners can expect more attacks on their patents on these grounds.

If a patent has been awarded for an invention that is 'obvious', it can be revoked because that means it lacks an inventive step. The test is whether an unimaginative but skilled person, with common general knowledge in this area, would think it was obvious. Common general knowledge is knowledge generally known by that skilled person, that they would automatically accept as reliable.

In a recent case, the court considered whether this included what is known as "secondary common general knowledge", that is, information that would not necessarily be to the forefront of their mind, but that they would routinely obtain or be provided with to tackle the problem – for example, review articles.

The court said that common general knowledge could extend beyond general information which the skilled person would know as a matter of course or could find in leading textbooks, such as information in review articles, but that the information:

  • Had to be "regarded as highly probable to be reliable".
  • Would certainly be found by the skilled person doing his job properly, as part of his normal approach to the task of identifying sources of information to use as a starting point.
  • Had to inform and guide the skilled person's approach to the problem from the outset.

The more that a "diligent search" was necessary, following leads and cross-references, the less likely that the information was common general knowledge.

Those seeking patents for inventions need to be sure that their invention could not be found to be obvious, given the extension of the test to include secondary common knowledge.

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