The apparently never-ending debate about whether cycling helmets should be mandatory for all cyclists resurfaced again with an article in the Guardian (12/10/15) looking at the different experiences of Seattle (which has made them compulsory) and Amsterdam (which has not).
A quick not-that-scientific-survey of commuting cyclists this week by me, indicated that 90%+ were wearing helmets. (Although probably 50% were wearing lycra so what does that prove?)
The Guardian discussion continues on Facebook and Twitter if you really want to get into "why-oh-why" mode.
The law on cycling helmets remains reassuringly uncertain. In Malasi v Attmed (2011) QBD, Judge Seymour QC reduced a cyclist’s award of damages by 80% when he was struck by a speeding taxi. Despite the defendant using upon him to take account of the lack of helmet and high-visibility clothing, the judge confined his decision to the failure to observe a red light.
In the famous decision of Griffiths Williams J in Smith v Finch (2009), the Judge indicated that the failure to wear a helmet could amount to contributory fault, despite the absence of any legal compulsion to wear them. Although on the facts, the Judge did not make any reduction as the nature of the injury would not have been prevented or alleviated by a helmet.
Of course, the Highway Code has recommended cycle helmets since at least 2007:
“… you should wear a cycle helmet which conforms to current regulations, is the correct size and securely fastened."
Many lawyers point out that the Highway Code also recommends high visibility clothing for walkers at night although I’m unaware of a decision in which a pedestrian who is run down is held partly liable for the failure to wear a reflective vest.
A short 10pp paper by the Dutch Cyclists Union in 2001 concluded, perhaps not entirely surprisingly, that bicycle helmets are not effective in the reduction of injuries to cyclists.
The continuing popularity of cycle hire in towns across the UK can only be sustained absent mandatory cycle helmets. These schemes require considerable investment from the private and public sector. A mandatory requirement that all riders (including tourists and causal users) had to wear helmets would inevitably kill the scheme stone dead. There is accordingly a significant political incentive not to make helmets compulsory.
Those acting in cycle cases should be aware of the relatively limited number of decisions involving the use of helmets and the (potential) impact on damages. These include the definitive seat-belt case of Froom v Butcher  1 QB 286 (which Griffiths J considered by analogy); Smith v Finch  EWHC 53 (QB); Brian Williams v Jacqueline Ashley (1999) – unreported; Drinkall v Whitwood  EWCA Civ 1547; (2004) 1 WLR 462; Probert v Moore   EWHC 2324 (QB) – considering the failure to wear hi-visibility clothing as a pedestrian; Phethean-Hubble v Coles  EWHC 363 – the failure to wear a helmet was not contributory to the accident/injury.
Pending an actual finding of contributory fault a High Court Judge for the failure to wear a helmet and/or a determination by the Court of Appeal, the issue will undoubtedly continue to be argued, with the circularity it has enjoyed to date.