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Crash Helmets: The Law

  • 24.04.2020
  • HughPotter
  • Personal-injury
  • Brain Injury Cycling Personal Injury serious injury Cyclist road traffic accident head injury road traffic collision traumatic brain injury Cycle helmets crash helmet

For many years Potter Rees Dolan has frequently acted for very seriously injured cyclists. All too often very sadly our cyclist clients have suffered life changing brain injuries usually because motorists have “not seen them”. The motorists’ insurance companies generally accept primary responsibility but increasingly have tried to reduce substantially the compensation they pay on the basis that the cyclist was at fault in part.

This can be very costly for a cyclist: if he or she is found to be 25% at fault, he/she loses 25% of his/her compensation.  In our larger claims for compensation, this can be a very considerable amount and run into hundreds of thousands of pounds and sometimes millions. 

These days motor insurance companies seem particularly keen to allege cyclists’ failure to wear a cycle helmet has caused the head injury.  Sometimes the allegation is justified, but all too often the allegation is made without any real basis and should be dismissed. We hope that some of our comments below will help cyclists decide what to do.

Should cyclists wear a helmet?

Cyclist biking at night wearing helmetCyclists tend to be passionate about this: some almost invariably wear a helmet and swear by them. Others don’t and curse them. Certainly, it isn’t a crime to ride a bike bare-headed and perhaps counter-intuitively there are epidemiological studies from Australia, New Zealand and Jersey which seem to indicate that compulsive helmet wearing puts off many would be cyclists to their and society’s overall health detriment. 

However, whatever general policy arguments there might be, in the past 10 years or so there has been a handful of reported civil cases where judges were at least in principle prepared to reduce cyclists’ compensation awards because of their failure to wear cycle helmets. In the High Court case of Smith -v- Finch  (22 January 2009) often relied upon by insurance companies, the Honourable Mr Justice Griffith Williams held that it would only be “sensible” for a cyclist to wear a safety helmet.  He came to that conclusion in part by the recommendation in the then prevailing Highway Code to wear a helmet and also by analogy with drivers who failed to wear a seat belt prior to when it became compulsory to do so (Froom -v- Butcher decided by the Court of Appeal including Lord Denning in 1976). 

There is no detailed analysis within the judgment about why wearing a cycle helmet was “sensible” and so this axiom is open to challenge.  Certainly, at the time Froom -v- Butcher was decided, there was a Bill going through Parliament to make seat belts compulsory, but there was and is no equivalent Bill for cycle helmets. Furthermore, there is empirical evidence that those wearing helmets are more at risk from overtaking motorists: a study published by Dr Ian Walker a psychologist at Bath University in 2006, indicated that on average motorists passed cyclists wearing helmets 8.5cm closer than those without. Perhaps this is because of the perception of a driver that a helmet wearing cyclist is more adept and so can be given a smaller margin when overtaking. 

Other cases followed but in none of the judgements was there set out clearly those circumstances in which a cyclist who failed to wear a helmet would be contributorily negligent. In Reynolds -v- Strutt (July 2011) Judge Oliver-Jones QC sitting as a High Court Judge was critical of a cyclist whose principal failure was the way he rode against another competitor (perhaps recklessly) in the context of a poorly managed work cycle race but did include his failure to wear a helmet. In Phethean-Hubble -v- Coles (February 2011) Judge Wilcox sitting as a High Court Judge accepted that Smith v Finch was the appropriate starting point but also recognised that wearing a helmet might actually increase the risk of injury by giving a cyclist a false confidence. Ultimately Judge Wilcox was not satisfied that on the facts of the case a helmet would have made any real difference and so made no finding of contributory negligence.

In the quite recent cycling case of Garwell -v- North Yorks CC (November 2019) Recorder Barnett recognised the argument that Mr Garwell’s decision not to use a helmet may have contributed to his injuries but left that argument for a later hearing when compensation would be assessed.

Plainly there will be circumstances when the court will say it is sensible to wear a helmet. However, in our view there will be occasions when not to wear a helmet may be sensible or at any rate not amount to contributory negligence. Much depends upon the precise circumstances including the nature of the ride – duration, speed, likely traffic etc – and the reasons for the cyclist not wearing a helmet. As Mrs Justice Cox said in Sinclair v Joyner [2015] “no court has yet decided that failing to wear a helmet actually amounts to contributory negligence, although they have come close (see Smith v Finch [2009] EWHC 53 (QB)). In the present case the Claimant was an adult enjoying a bicycle ride in the countryside on a sunny day. There was no medical evidence adduced to show that failing to wear a helmet made the Claimant’s injuries worse, and the subject was not addressed in submissions. I therefore reject that allegation of contributory negligence in this case.”

Causative breach

The bad news for motor insurance companies is that they must do more than establish that a cyclist did not act sensibly by failing to wear a cycle helmet.  In many ways, that is simply the start of a difficult journey for the insurance company.  It must prove that failing to wear a helmet probably made a difference.  In Smith -v- Finch, the bare-headed cyclist Smith was knocked off by Mr Finch who was driving at an “excessive speed”. Mr Justice Griffith Williams found that the unlucky Mr Smith hit the ground at a speed in excess of 12 mph. He also found that Mr Smith’s injury was in large part to an area of his head (the back) unlikely to be given much protection by ‘modern helmets’ (as judged at the date of Mr Smith’s accident). He concluded that however daft, Mr Smith’s failure to wear a helmet his compensation should not be reduced because the insurers had not proved that it made the slightest difference to his injuries. 

As a consequence, Mr Smith received all of his compensation.

This and subsequent cases illustrate the hurdles motor insurers must surmount before any Court will be persuaded to reduce a cyclist’s compensation. It is important to remember that it is the responsibility of the insurers to prove the difference a proper helmet would have made. The hurdles include proving:

  1. That the cyclist was not in fact wearing a helmet and of course in some accidents, helmets become faultlessly dislodged;
  2. Where a cycling helmet was worn, it was not ‘proper’. In this context it is not enough for an insurer to show there were better perhaps much better helmets available. It is enough for the cyclist to show that his/her met the requisite safety standard and is in good order. 
  3. If not worn the difference a proper helmet would have made. The first question is what is the crashworthiness of the helmet the cyclist should have worn? This is important because crashworthiness of approved helmets differ quite markedly. If the cyclist failed to wear his/her own it is at least arguable that the starting point is the cyclist’s actual helmet if it met the requisite safety standard and was in good order. This works to the cyclist’s advantage if his helmet is fine but towards the lower end of crashworthiness.

The second question is what difference the actual or hypothetical helmet would have made. This is often a technical argument between experts. Often the general point is made that broadly cycle helmets are not designed to afford protection at impact speeds much over 20 mph. They are also less able to withstand concentrated forces of an impact on a ‘sharp’ surface such as a kerb edge.

Medical evidence

If the motor insurers have been able to prove on a balance of probability that wearing a crash helmet would have given the cyclist protection, they then must prove that the brain damage suffered by the cyclist would have been avoided. This is not easy. Mr Justice Griffith Williams found there was no contributory negligence on the separate basis of Mr Finch’s insurers failure to adduce any medical evidence to relate Mr Smith’s hypothetical crash helmet to the brain injuries he suffered/would have suffered. In other words, it is not enough for an insurance company to show that a cycle helmet would have afforded protection in general. 

This has caused insurers particular evidential problems where the brain injury is a so-called diffuse axonal injury caused by rapid rotation of the brain inside the skull as this would have occurred in any event at least to some degree or where there are multiple injuries to the same brain, for example through a contrecoup injury.


Motor insurers very frequently allege failure by a cyclist to wear a helmet is contributory negligence and so seek 25% deduction (if the injuries would have been avoided pretty much entirely) or 15% (if the brain injury would have been significantly less). Any individual cyclist should be very slow to agree to such deductions without clear and specific evidence from the insurer in support of its case. Instead the insurers should be told to put a lid on it.

Written by Hugh Potter, Senior Partner & Head of Personal Injury, and Jeremy Smith, Senior Personal Injury Solicitor.