"29. However, the search for justice requires some difficult reconciliations of conflicting principles, and there is a strong public interest in finality in litigation. The rule or practice embodied in the authorities mentioned earlier in this judgment is not regarded as a matter of technicality, but of justice to a respondent who may be plunged into yet more litigation: see for instance Sir John Donaldson in GKN (Cwmbran) at p.219 and Arnold J in Kumchyk at p.1123. Sometimes the rule does result in a case being decided on a basis of law that is not merely arguably, but demonstrably, wrong by the time it reaches the appellate court: Wilson v Liverpool Corporation is itself a striking example."