Mentor Corporation v Hollister Incorporated: ChD 1991

The court considered the meaning of the phrase a ‘person skilled in the art’ in the context of a patent claim.
Aldous J said: ‘The section requires the skilled man to be able to perform the invention, but does not lay down the limits as to the time and energy that the skilled man must spend seeking to perform the invention before it is insufficient. Clearly there must be a limit. The sub-section, by using the words, clearly enough and completely enough, contemplates that patent specifications need not set out every detail necessary for performance, but can leave the skilled man to use his skill to perform the invention. In so doing he must seek success. He should not be required to carry out any prolonged research, enquiry or experiment. He may need to carry out the ordinary methods of trial and error, which involve no inventive step and generally are necessary in applying the particular discovery to produce a practical result. In each case, it is a question of fact, depending on the nature of the invention, as to whether the steps needed to perform the invention are ordinary steps of trial and error which a skilled man would realise would be necessary and normal to produce a practical result.’


Aldous J


[1991] FSR 557


Patents Act 1977 72(1)(c)


England and Wales


CitedValensi v British Radio Corporation CA 1973
The court considered the test for deciding what degree of knowledge, skill and perseverance the skilled man was assumed to have as a ground for revocation of a patent on the associated basis. There had been a mistake in the specification of the . .

Cited by:

Appeal fromMentor Corporation v Hollister Incorporated CA 1993
Lloyd LJ added to the guidance at first instance:
‘In each case sufficiency will thus be a question of fact and degree, depending on the nature of the invention and the other circumstances of the case.
But if a working definition is required . .
CitedGenerics (UK) Ltd and others v H Lundbeck A/S HL 25-Feb-2009
Patent properly granted
The House considered the patentability of a chemical product, citalopram made up of two enantiomers, as opposed to the process of its creation, questioning whether it could be new or was insufficient within the 1977 Act.
Held: The appeal . .
Lists of cited by and citing cases may be incomplete.

Intellectual Property

Updated: 18 May 2022; Ref: scu.304529