check this out
http://www.thisislondon.co.uk/standard-mayor/article-23484376-details/
Boris%3A+I+admit+I+need+to+start+wearing+a+helmet/article.doInterestingly to quote the CTC
CTC feels that Boris, like any cyclist, should be free to choose whether or not to wear a helmet. The evidence suggests pressure to wear helmets merely deters people from cycling, without detectably improving the safety of those cyclists who remain. Holland, where helmet-wearing is almost unheard of, has far higher cycle use and better cycle safety. We should see Boris as a role-model as he proves that anyone can cycle in normal clothes.This is a road riding view I'm sure.