I can never see the safety lobby's obsession with helmets. In a country where there's no compulsory motorcycle helmet law, I'd say that fatalities would be reduced by half if wearling a lid became statutory. Coming off a motorbike, you're likely to be going a fair lick. You're likely to be thrown a respectable distance or slide/bounce and hit your bonce on something. Cyclists? Under what circumstances is a helmet going to make any difference? If you're going round HPC onto Grosvenor Place on the inner and someoene puts you head first into one of those thoughtfully placed bollards outside Lizzie Batts's back garden, yeah. If you're thrown over the bars and land on your head, yeah. What percentage of fatal "accidents" (I hate that word; most cycling fatalities are not accidents) fall into those categories? Two percent? Less? A helmet won't help if your noggin goes under the wheel of a ten ton Luton. How often did we see pile-ups in road races with riders doing 65kph in the pre-helmet days? And how often did any of them suffer serious head injuries? None of the cyclists killed in London in the past couple of years would have been helped by a helmet. (A brain would have saved most of them, but this is 2010 and they were mostly English so, they obviously didn't have one between the lot of 'em.) Obviously any collisions in which a helmet saved a cyclist don't make the news, but I'd still say that number of collisions would be very small indeed. Cyclists need to veer sharply away from the topic of helmet paranoia, or they will be made compulsory as soon as Noo Layba gets back in.
FWIW, a recent report broadcast on the 'More or Less' show concluded that there simply wasn't enough data to draw any conclusions one way or another about the efficacy, or otherwise, of helmets. The presenter, Tim Harford, cycles and uses a helmet when he does so.