“Costs of Patent proceedings and theCPR 24 . In respect of all intellectual property matters the general rule is that the CPR and associated practice directions apply, unless a rule in Part 63 or its practice direction provides otherwise (CPR 63.2 ). There is no such rule. So, subject to the two statutory provisions discussed above, the general rules apply as much to patent actions as to any other action. 25. It follows that all the factors and matters set forth inCPR 44.3 apply to how the court should exercise its discretion as to costs. Prior to the CPR a party who was successful overall was not normally deprived of its costs of an issue it took unsuccessfully unless it has done so unreasonably, see Re Elgindata (No. 2)[1992] 1 WLR 1207 . But since the CPR a more issue-by-issue approach is appropriate, see Summit Property v Pitmans[2001] EWCA Civ 2020 , applied in a patent action, Stena v Irish Ferries[2003] EWCA Civ 214 . Even before the CPR an issue-by-issue approach was, as an exception to the Elgindata approach, applied in patent actions because of the "large number of issues and the very extensive costs that can be incurred" per Aldous LJ in Rediffusion v Singer Link[1993] FSR 369 at 410. 26. An issue-by-issue approach is therefore one that should be applied so far as it reasonably can. On the other hand such an approach is not the be-all and end-all. Whether or not "it was reasonable for a party to raise, pursue or contest a particular allegation" remains a relevant factor to be taken into account as part of the conduct of the parties (seeCPR 44 rule (3)(a) and (5)(b). The impossibility of great precision 27. Before turning to this particular case I should say something about this. Although an issue-by-issue approach is likely to produce a "fairer" answer and is likely to make parties consider carefully before advancing or disputing a particular issue, it should not be thought that it is capable of achieving a "precise" answer. The estimation of costs, like that of valuation of property, is more of an art than a science. True it is that one can measure certain things (such as pages of witness statements or transcript devoted to a particular issue) but they can only be indicia to be taken into account. It would be dangerous to rely upon them as absolutes. Indeed brevity of a document, or a cross-examination, may be the result of great care: was it Hazlitt who apologised for the length of a letter, excusing himself on the grounds that he had not enough time to compose it? 28. It follows that there is no "precise" figure of costs which, in theory with perfect measurement tools, one could reach. The best that can be achieved is an estimate which is necessarily going to be somewhat crude”
“The correct approach is to ask oneself three questions. First of all, who has won; secondly has the party that has won lost on an issue which is suitably circumscribed to deprive that party of the costs of that issue and, thirdly, is the case a suitably exceptional one to justify making a costs order on that issue against the party who has won overall.”