James Mellor QC and Charlotte May QC appeared for the Respondent/Appellant and Third Parties, ‘Smith & Nephew’, in this appeal which related to the construction of the words ‘between 1% and 25%’ as contained in the claim of a patent owned by the Appellant, ‘Convatec’. The patent concerns a process of silverisation of gel-forming fibres used in wound dressings and the words being construed related to the concentration of a binding agent in that process.
Allowing Convatec’s appeal, Kitchin LJ held that in the context of the patent the words would be understood by the skilled person on a ‘whole number’ basis and thus they would cover values ≥ 0.5% and < 25.5%. In doing so the judge rejected arguments that the skilled person would understand the words as exact limits or based on a ‘significant figures’ approach.
James Mellor QC and Charlotte May QC were instructed by Bristows LLP.