Mr Justice Pumfrey adopted with approval the approach of Mr Roger Wyand QC in Mayne v. Pharmacia  EWCA Civ 137:
"(a) The first, overarching principle, is that contained in Art.69 [of the European Patent Convention] itself . . .
(b) Article 69 says that the extent of protection is determined by the terms of the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.
(c) It follows that the claims are to be construed purposively – the inventor's purpose being ascertained from the description and drawings.
(d) It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity . . . Purpose is vital to the construction of claims.
(e) . . .
(f) Nonetheless purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Art.69 itself. It is the terms of the claims which delineate the patentee's territory.
(g) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements . . .
(h) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context . . .
(i) It further follows that there is no general "doctrine of equivalents" . . .
(j) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.
(k) Finally purposive construction leads one to eschew what Lord Diplock in Catnic
[Catnic Components Limited v. Hill & Smith Limited  RPC 183] called (at p.243): 'The kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge'."
The judge added that one has to consider how the specification would be construed by a person skilled in the art which in this case would be a maker of probes.
The application of those eminently sensible principles will vary from case to case and anyone wanting to find out how Mr Justice Pumfrey applied them in this case had better read it. All I will say is that he did not consider that the patent had been infringed. It appears to me that that was because of the narrowness of the claims but I didn't draft them and I wasn't there in court. The case is still an instructive one to read.