Skip to content

The cycle helmets debate – legal aspects

4 July 2011

helmetsHelmets are probably the most controversial part of cycling law.

They’re not compulsory for cyclists in the UK, although attempts have been made quite recently to bring in legislation requiring them (and a Bill to make helmets compulsory in Northern Ireland is still before the legislative assembly there).

But that’s not fully the end of the matter. The Highway Code recommends that cyclists should wear helmets, and the courts have found cyclists who haven’t worn helmets to be at fault in certain respects.

This post doesn’t argue either way, for or against compulsory helmets. I’m not convinced there’s that much difference between riding on the road on a bike (no helmet necessary) and a 50cc scooter (for which, as far as I understand, a motorbike-grade helmet is compulsory). But, on the other hand, compulsion would probably damage cycling rates in the UK (which are already very low), and I’m not sure that cycle helmets as they’re currently designed are all that much use.  

I thought I’d describe the legal background to the debate, to help people make up their own minds about helmets.   


There’s no legal requirement to wear a helmet when you’re cycling in the UK.

In Northern Ireland, there is a Bill which would make it an offence to cycle without wearing a helmet which is still before the legislative assembly. The progress of the Bill was held up earlier this year, when the “committee stage” was not properly completed. It seems likely that there will need to be a new committee report before the Bill can be progressed further. At the moment it’s not clear exactly what is going on, nor when the Bill will be voted on again.

Proposals to make helmets compulsory across the UK are also occasionally discussed in Parliament. Most recently, in 2004, there was an attempt to introduce a requirement for children to wear helmets while cycling. That proposal failed through a lack of interest or support.

In fact it’s arguable that primary legislation (the sort made by Parliament) wouldn’t be necessary to introduce compulsory cycle helmets in the UK. Section 81(1) of the Road Traffic Act 1988 already empowers the Secretary of State to “make regulations as to the use on roads of cycles, their construction and equipment and the conditions under which they may be so used”. It seems arguable that rules requiring helmets would be regulations as to the use on roads of cycles or as to the conditions under which bicycles may be used, so could be made under section 81(1). To do this the Secretary of State wouldn’t need the support of Parliament (although any regulations could be annulled by Parliament). (RTA s. 81(1); 195(3))

But there are also arguments the other way – that helmet compulsion would be a safety provision, rather than a construction and use provision, and therefore the relevant rules would have to be made under Part 1 of the 1988 Act (which would require primary legislation through Parliament). This is how the compulsory helmets rule for motorbikes was created – as a safety provision under Part 1 of the 1988 Act. (RTA s. 16; Motor Cycles (Protective Helmets) Regulations 1998 (SI 1998/1807))

The point is arguable either way. But any move by the Secretary of State under section 81 would be open to challenge in the courts (and would be very controversial), and this probably makes it unlikely.

So are there any legal consequences if you don’t wear a helmet?

Rule 59 of the Highway Code recommends that “you should wear a cycle helmet which conforms to current regulations, is the correct size and securely fastened”. It’s not a compulsory provision, but the courts can take it into account in determining your liability. (Highway Code rule 59; RTA s. 38(7))

So, for example, rule 59 of the Highway Code would be relevant in determining whether it’s negligent to ride a bike without wearing a helmet. Of course it’s difficult to see how failing to wear a helmet could hurt anyone else. So it’s difficult to see how it could lead to liability for negligence (being sued and made to pay damages).

But the courts have considered this issue in the context of contributory negligencewhere the person who wasn’t wearing a helmet is injured in an accident, and sues the person who caused the accident.

Contributory negligence

For example, a car driver knocks over a cyclist who isn’t wearing a helmet, causing the cyclist to suffer head injuries. The cyclist sues the driver for damages. One of the defences which the driver can raise (as a way of trying to avoid paying full damages) is contributory negligence – arguing that the injury was caused or contributed to by the cyclist’s negligence in failing to wear a helmet, so the driver shouldn’t have to pay for the injury in full.

In this context, for contributory negligence to be proved, two things are necessary:

  • The cyclist has to have been at fault in some respect; and
  • The cyclist’s fault has to have caused or contributed to their injury.

This is an issue which the courts have dealt with a number of times. On the two most recent occasions, they have held that the cyclist who rode on the road without wearing a helmet was at fault – so the first part of the test for contributory negligence was satisfied. (Smith v Finch [2009] EWHC 53 at §§43-45; Phethean-Hubble v Coles [2011] EWHC 363, §136)

A few things need to be said about this. First, the cases deal with cycling on the road. The position might be different for young children, or for cycling in a park – it’s not clear, but it may be that in those situations, riding without a helmet wouldn’t amount to being at fault. (A (A Child) v Shorrock [2001] CLY 4466; Swinton v Annabel’s (Berkeley Square) Ltd [2005] CLY 2842)

Secondly, these cases don’t necessarily mean that the courts will always take this view – it’s probably not entrenched as a rule of law yet. So, for example, The Cycling Lawyer has written this paper (for a legal audience) arguing that it shouldn’t count as contributory negligence to ride without a helmet. But it’s worth noting that the paper was presented before the decision in the Phethean-Hubble case, which took the opposite view. 

Most importantly, though, the courts have so far declined to hold that any individual cyclist’s failure to wear a helmet has caused or contributed to their head injury.

In the Phethean-Hubble case, Wilcox J said that “the literature establishes that cycle helmets are generally beneficial in head injury cases. It is clear that a properly designed helmet worn by a cyclist at speeds of up to 12mph who falls 1.5 metres and hits his head on the pavement is afforded a high level of protection.” But, in the case before him, the helmet could have had only “the most minimal effect”, because of the nature of the impact and the head injuries which the cyclist suffered. (Phethean-Hubble at 137, 139)

Similarly, in Smith v Finch, Griffiths J found that the cyclist’s speed of impact with the ground was likely to have been greater than 12mph, and the nature of the impact was such that a helmet would not necessarily have helped. (Smith v Finch at 53-56)

So there was no evidence that the injuries which were being considered by the courts would have been prevented by wearing a cycle helmet. As a result the second part of the test for contributory negligence (set out above) has never been satisfied. This means that, so far, no cyclist has had their damages for a head injury reduced for contributory negligence because they weren’t wearing a helmet.


At the moment, if you cycle in the UK without wearing a helmet you’re not committing any kind of offence. That may change in Northern Ireland, depending on what happens with the current Bill.

Similarly, so far no cyclist who has suffered a head injury in a traffic accident has had their damages reduced for contributory negligence for not wearing a helmet. In the light of the current scientific evidence, it seems likely that a helmet will only be found to have made a difference in a case where the speed at which the cyclist hits their head is relatively low.

Of course this reflects the point often made by anti-helmet campaigners: given the way cycle helmets are made and tested, they’re more likely to be useful if you fall off your bike, and less likely to be useful in a collision with other traffic.

All of this makes it especially clear how important it is to avoid being hit. The court cases on cycle helmets are sad stories of everyday journeys ending in lives being destroyed. Whether or not you choose to wear a helmet, stay safe!


Photo by joshgray from here:

New: follow UK Cycle Rules on facebook!


  1. Mike Chalkley - Chair Bournemouth Cycling Forum permalink
    4 July 2011 14:49

    “I’m not convinced there’s that much difference between riding on the road on a bike (no helmet necessary) and a 50cc scooter” – presumably you’re a ‘sports’ cyclist? To me there’s a huge difference.

    I don’t doubt that many current cyclists are able to troll about at 30mph+ and in that situation you’re probably right. The difference comes when you look at cycling in terms of the current ‘ordinary’ non-cyclist who is scared to tackle the road conditions in the UK.
    If your mum (or gran) were to start using a bike to pop to the shops, she would most likely never exceed 10-12mph. If she were to take the same journey on moped, she would likely reach 30mph wherever congestion allowed.

    My wife and I cycle as often as we can, our last trip of 26 miles had an average speed of 9mph. I think we touched 20 on a downhill.
    People who ride bikes now will, on average, cycle faster than the general population would if we could get a real shift in modal share. This is one aspect of helmet compulsion that’s often overlooked.
    On the ride I just mentioned, we travelled down the lovely Castleman Trailway, an onld stretch of railway bed that used to run between Wimborne and Upton near Poole. It’s flat, bikes & walkers only but the number of people I saw with helmets on was astounding.
    Helmet promotion puts the fear of god into people. It’s bad for cycling.

    On a final note, take RoSPAs guidance for teachers they recommend for a class of 6-7 yr olds…”Draw faces on two eggs and give them names (the pupils could make suggestions).
    Tell the children that they are going to ride their bikes, but one doesn’t like wearing a
    helmet. Ask them what would happen if he fell off his bike. Hold the egg one metre
    above the floor and drop it, watching it smash.” (

    No wonder people don’t want to ride!

    • 4 July 2011 15:59

      thanks mike – some good points, interesting stuff

    • Paul Jakma permalink
      4 July 2011 22:37

      Great post. The other factor in wearing helmets is risk homeostasis: drivers and cyclists will take greater risks, e.g. a study showed drivers pass closer on average to helmeted cyclists. There’s a recent study of australian helmet law which, though claiming to show a decrease in the period around the introduction of the law, seems to show a longer-term increase in head injury rates – despite a stable-ish accident rate.

      The other factor is the macro-social effect of discouraging cycling. Whatever gains there may be to an individual once they are actually involved in an accident, may be extremely small compared to the detrimental effect on public health over time of sedentary life-styles.

      Obesity is on balance the FAR greater risk to public health.

      When I see cyclists in hi-viz & helmets, I see rolling “Cycling is dangerous!” advertisements.

  2. 4 July 2011 15:53


    I presume they’re referring to the usual helmet test, which is putting a 5kg magnesium headform into a helmet and letting it drop 2 metres or so onto anvils of varying shape and seeing whether the liner compresses without breaking. If this is what they’re referring to, they’ve made a clear mistake.

    The head is afforded protection if falling 1.5 metres from a _stationary_ bicycle, or when the head is travelling at 12mph. Travelling at 12mph AND falling 1.5 metres results in kinetic energy that exceeds the standard test and therefore what the helmet is certified to absorb.

    As for Northern Ireland, the CTC specifically asked the committee to which they gave evidence whether the bill would have to go through all stages again, and they were told it would have to. So it’s completely back to the beginning again, but with it now being clear that Sinn Féin and the DUP are not interested in this bill, and they both have more seats in the Local Assembly than earlier in the year. So it’s highly unlikely to be passed any time soon.

    • 4 July 2011 16:02

      hi dermot – i must admit i’ve found it difficult to find anything online describing exactly how cycle helmets are tested. are you relying on particular sources, or have you got personal knowledge?

      i also tried to calculate how fast a head would be travelling after falling 1.5 metres, to see if that was the explanation for the 12mph thing, but didn’t get very far!

  3. 4 July 2011 15:54

    Sorry, tried using angular quotes there. I meant to quote off this:

    In the Phethean-Hubble case, Wilcox J said that “the literature establishes that cycle helmets are generally beneficial in head injury cases. It is clear that a properly designed helmet worn by a cyclist at speeds of up to 12mph who falls 1.5 metres and hits his head on the pavement is afforded a high level of protection.”

  4. Mike Chalkley - Chair Bournemouth Cycling Forum permalink
    4 July 2011 19:23

    Try – the whole site’s good but this is info from an expert in helmet testing.

    • 4 July 2011 20:31

      Yes, I had that in mind, and this too:

      This is also by Brian Walker.

      Note the claim that helmet manufacturers aim to pass the weakest standard (and then I imagine only just, in order to keep profits higher). In fact, Walker’s tests in 1998 found
      some helmets didn’t even past the weakest test (EN1078 standard), which surprised me.

      Off the top of my head, I think this is the correct way to work out the velocity of a body dropped from a height.

      Energy = mgh (potential energy) = (1/2)mv^2 (kinetic energy)
      m is mass, g acceleration due to gravity, h the height from which the helmet is dropped, and v the final velocity at impact

      Simplifying: gh = (1/2)v^2

      So 9.807m/s/s x (2 metres) = 1/2 x v^2

      v = 6.263 m/s

      So a velocity of 22.55km/h, or about 14mph.

      If you drop from 1.5m, it’s 19.53km/h or about 12mph

      So the 12mph claim applies to a 1.5m fall from a bicycle that isn’t actually moving.

  5. 5 July 2011 19:17


    Helmets are made compulsory in the Bicycle Safety Act 2012 for all cyclists on the road.

    Some thoughts. A 9 year old child is stopped by a police officer for not wearing a helmet. What course of action could the police take? Other than asking him/her, or his parents, in future to wear a helmet, not much.

    A 10 year old child is stopped for not wearing a helmet. If a fine is issued, what are you going to do if the cyclist doesn’t pay it?

    Interestingly, children are at most risk of a possible head injury but are the group who would be most difficult to enforce the law against.

    • 6 July 2011 09:21

      hi tom

      i think the approach that the draft bill in 2004 took was to penalise the parents for causing or permitting the child to ride without a helmet (or something similar) – then enforce the fine in the usual way (ultimately, with court proceedings if not paid). not without its difficulties, obviously.

  6. 5 July 2011 22:35

    Although a self-selecting sample I think this video of Dr. McNally (Scientific Director, Institute of Biomechanics, University of Nottingham) is pertinent here:

    • 6 July 2011 09:30

      thanks henz – powerful stuff, and good to see some pro-helmet material too!

      • 6 July 2011 14:00

        I’m afraid I can’t watch that video right now (restricted bandwidth), but I assume from the comments beneath that the victim’s helmet broke and is assumed to have saved his life. Anecdotes are a powerful friend to helmet advocacy, but have no scientific validity in themselves. There are far more “helmet saved my life stories” than there ever were cyclists with serious brain injuries.

        Looking at very large numbers of helmet-wearers (which has far more scientific validity) should show up a life- or injury-saving effect. So far the effect is very hard to discern, which suggests at the very least that the protection is modest. And that is what me might expect when they are certified for 1.5m falls (and worn incorrectly by most people).

        A recent review of case-control studies by Elvik suggests that once neck injuries are taken into account, the net safety effect of helmet-wearing has been zero — that is, helmets seem to prevent certain head injuries, but translate them into neck injuries.

        On another note, we probably should avoid the implication that somewhat sceptical contributions are “anti-helmet”. The term appears in both the original post and in the comments. Some sceptics are probably “anti-helmet”, for various reasons, but a great many just are perturbed by the grand claims made for a very limited form of protection, that is in any case, as I said, worn incorrectly by most people.

        Helmets almost certainly prevent scalp lacerations and perhaps simple skull fractures, for which reason they are probably of some value, but making them compulsory seems excessive, given that outside competitive cycling such injuries are rare, and in any case rarely life-altering.

      • 6 July 2011 14:13

        Actually, I may be misleading you on Elvik’s paper. The relevant quote is:
        “no overall effect of bicycle helmets could be found when injuries to head, face or neck are considered as a whole.”

        Which I assume means that some head injuries are prevented, but some neck injuries are caused that otherwise would not have happened. It doesn’t necessarily mean that head injuries are prevented in some cases but are translated directly into neck injuries in those same cases.

  7. 6 July 2011 14:14

    Sorry to hog the thread. I should give the name of the paper:
    Publication bias and time-trend bias in meta-analysis of bicycle helmet efficacy:
    A re-analysis of Attewell, Glase and McFadden, 2001

    Anyway, that’s enough from me.

Comments are closed.

%d bloggers like this: