Nortones2 said:
Its because most journalists are not aware of the principles of judicial precedent. No High Court judgement can set a precedent except on inferior courts: it's persuasive only on itself. And it has to be relevant to the circumstances, so if the case did not decide whether a helmet would prevent harm, at least to some extent, then it would be fairly easy to eliminate that argument (or distinguish in legal terms). Not until a case is appealed to a higher jurisdiction can a binding precedent be set. Here is a useful link:
http://legal-directory.net/english-law/rules-of-precedent-civil-courts.htm
What Nortones2 said. This case does not introduce a precedent as it's a High Court case.
Also, the Beachcroft article appears to be from their insurance litigation dept, which suggests to me that they may have been acting for the motorcyclist/his insurers. Anyway, they are writing a precis for an insurance-oriented audience. Of course it would be a welcome development in their view and it may well encourage a couple of insurance companies to bring out the medical evidence next time they are confronted with this situation.
Finally, as CotterPin has said, there's not really a problem with arguing contributory negligence against a non-helmet wearer. The Froom v Butcher case mentioned involved someone not wearing a seatbelt in a car and was deemed to have been to some extent negligent by not doing so. Damages were reduced (not thrown out, reduced) because in that case it was easier to bring evidence that wearing a seatbelt would have reduced the extent of the claimant's injuries. As has been mentioned here (and elsewhere ad nauseum) the evidence is far sketchier that even wearing a helmet would reduce the extent of the injuries received.
I'd be surprised if barristers haven't been raising this point for ages - some of the case law I vaguely remember from my studies suggest that contributory negligence is raised on even the mildest pretext. It's just that someone picked up on this particular case.
No precedent, no law by the back door.