Emson v Hozelock  EWCA Civ 871
The Court of Appeal in Emson v Hozelock ( EWCA Civ 871) was asked to consider whether an invention relating to expandable hoses, which was relatively simple in technical terms, was obvious in view of a similar hose disclosed in a remote technical field.
The Court of Appeal judges heard Emson’s appeal to overturn a High Court decision (covered in a previous article here) finding their GB and EP(UK) patents infringed but nonetheless invalid for being obvious in view of McDonald, a prior art document relating to a self-elongating hose for supplying oxygen to an oxygen mask for aviation crew.
Interestingly, the validity and infringement of Emson’s GB patent was previously litigated in proceedings brought against different defendants with a different outcome, Blue Gentian v Tristar  EWHC 4098 (Pat), a decision which was confirmed on appeal. In this decision, the judges had considered the same question of whether the invention was obvious in view of the same prior art document.
The difference in outcome was down to the facts of the case, and in particular, the evidence provided by the expert witnesses. In the decision issued in respect of the present appeal, Arnold LJ notes that in Blue Gentian “neither of the experts had experience in the design or manufacture of hoses”. In the present case, however, the expert witness provided by the defendants (Hozelock) – described as an “impressive witness” by the judge – had experience in the manufacture and design of garden hoses, as well as technical hoses.
The UK test for whether an invention possesses an inventive step (and therefore is worthy of patent protection) first involves consideration of who is the skilled person in the relevant technical field, followed by identifying their common general knowledge. The next steps are to identify the differences between the alleged invention and the prior art, and then decide whether the steps to arrive at the invention would have been obvious to this notional skilled person, without hindsight knowledge of the invention in the patent.
In the instant case Arnold LJ was satisfied, based on the evidence of the expert witnesses, that the skilled person was not specifically a garden hose designer but a designer of hoses in general, thus having knowledge of technical hoses. McDonald, a document describing an expandable hose but in the field of aerospace, was therefore considered to be within reach of the skilled person for them to combine with their common general knowledge of garden hoses, leading them to the invention.
In considering this point, Arnold LJ noted that there was nothing in the disclosure of McDonald to indicate that it would be incompatible with garden hoses, and so the skilled person would have no difficulty in transposing its teaching.
Many other lines of argument were put forward by Emson, including that factors such as commercial success, the invention satisfying a ‘long-felt want’, and the device of the prior art being long disregarded and unused, should have been given weight. However, these arguments were not deemed sufficient by Arnold LJ to overturn the finding of obviousness.
Perhaps the most interesting part of this decision is the fact that the three judges could not all agree on whether the patents were obvious.
Floyd LJ, the dissenting judge, reminds us that hindsight is a particular danger where the invention is a simple one. Floyd LJ considers the first instance judge had erred on two points.
First, in that the judge had treated McDonald as a real, practical machine, as opposed to a ‘mere paper proposal’. Floyd LJ highlights that care is needed with unworked proposals in patent specifications, which should have “less force in an obviousness argument than those which have been implemented or are well known”, as they would be approached with a high degree of scepticism by the skilled person. Floyd LJ also considers the judge ignored expert evidence suggesting it was not clear exactly how the hose in McDonald worked.
Second, Floyd LJ considered that the evidence indicated that the skilled person working with garden hoses is not presented with anything in McDonald of which he is in real need; McDonald describes itself as space-saving, but this is merely a necessary design consideration, and a problem that has already been solved for garden hoses. Floyd LJ highlights the fact that the evidence had shown that garden hoses had not changed in many decades, and states that this should have been considered a material factor.
The third judge, Henderson LJ, was left with the deciding vote on the matter. Henderson LJ, unlike the other two judges, is not a specialist patents judge. However, he found himself unable to agree with Floyd LJ’s repeated dismissal of McDonald as “a mere paper proposal”, and found the patents obvious because he considered that their core inventive concept was unambiguously disclosed in McDonald.
On the face of it, this decision may seem harsh on the inventor. All of the judges acknowledge this in their judgements, expressing sympathy for the sole inventor for devising an invention that was undoubtedly commercially successful.
In conclusion, this decision illustrates just how important the selection of an expert witness can be in convincing a court as to how best to determine the identity of the skilled person, and in turn how the identity of the skilled person (and their common general knowledge) can be pivotal to the outcome of a case. It also provides some useful indicators to consider when arguing for inventive step over prior art documents from remote technical fields. It will be interesting to see how this case develops, should it be taken to the Supreme Court.
The full judgement can be found here.