I am often asked which expert I would go to on behalf of a Claimant to give an opinion as an “expert in helmets”.

Meaning of course that a Defendant, generally in a road traffic collision case is seeking to establish that the Claimant has contributed to his or her injuries by failing to wear a bicycle helmet or even fasten it sufficiently, and so should have his or her damages reduced accordingly.

I wish the answer was a straightforward one as I see the questioner’s eyes roll slightly as I launch into what is clearly going to be a long-winded tirade…bear with me.

There is no single recommendation.

The problem is that no one expert from any particular discipline is likely to be able to give the court a definitive opinion on the balance of probabilities, as to whether a cycle helmet would, or would not have, prevented an injury.

In theory, it would be much easier to give that opinion in a damages case involving less serious injuries. It would be easier for instance for a Defendant to show that a simple fracture to the skull is less likely to have occurred if there was a helmet taking the initial force of the impact.

Anecdotally at least, it would appear that such an injury may well have been prevented or reduced, but that sort of case has never, as far as I am aware, come to the attention of the Court and that makes sense; the only cases where Defendant insurers are likely to make a serious play in this regard is where there has been a brain injury of sufficient seriousness for it to make a meaningful difference to the amount of damages they will have to pay out.

For that reason, I will ignore the lesser injuries for the time being and concentrate on the significant traumatic brain injuries we regularly see in cycling collision cases.

Most of the time these injuries will have occurred at closing speeds significantly above the c12mph (Europe) or c14mph (US) closing speeds cycling helmets are currently tested to.

Smith v Finch [2009] EWHC 53 (QB) is still the best authority out there, despite the judgment, unhelpfully in my view, failing to sufficiently define the term “fault” when referring to a helmetless rider – the Defendant motorcyclist in that case sought a deduction of 15% for the cyclist he collided with failing to wear a helmet.

The Court made it clear that lack of a helmet could be considered in relation to allegations of contributory negligence, but could not go on to make such a finding in that case because the closing speed was so much higher than 12mph that it was not scientifically viable to assert that a helmet would have made any difference at all to the serious injuries sustained.

Most cases that get to any sort of advanced stage will be of that ilk – a serious brain injury case where there are significant forces involved, usually involving a collision with a motor vehicle and almost indefinitely at a closing speed (i.e. speed cycle moving at plus speed motor vehicle travelling at) of very much higher than 12-14mph.

It is tempting, I think, to be brave as a Claimant and not offer any causation evidence on this at all, over and above that which you would normally serve - particularly for example in cases of “Diffuse Axonal Injury” (widespread and hard to define damage to multiple areas of the brain as a result of, for example acceleration/deceleration forces and/or the brain being thrown around inside the skull).

This is, after all, always in the context of a Defendant raising a Defence of contributory negligence and as such the burden of proof is firmly on the Defendant to show on balance of probabilities that a helmet would have prevented/reduced the injuries sustained.

I am yet to be convinced that it is at all possible for a Defendant to do in this scenario. The very least you should do as a Claimant representative is always seek from whichever procedural Judge you are appearing before, sequential service of expert witness evidence on the point.

If you have not yet commenced Court proceedings, seek disclosure of the evidence the Defendant seeks to rely on in advance. If the Defendant refuses to provide advance disclosure, my view is that this would warrant issuing proceedings to seek a case management order on it.

In this way the Claimant, as must be appropriate in the circumstances, will be able to assess whether the Defendant has made out a reasonable case on the issue, before going on to incur additional and substantial costs in obtaining expert witness evidence.

It may be the Claimant does decide the Defendant has not been able to prove its Defence of contributory negligence and chooses not to answer the evidence with the Claimant’s own experts.

I can well understand though that it would be a very brave thing indeed to turn up to Court armed with no evidence at all to rebut the Defendant’s stated case. What sequential exchange will also do is direct you to the disciplines you would need to seek evidence in to answer the specific allegations in the Defence.

Having said all of that, in many cases you will either face an order for simultaneous exchange, or the Defendant will produce evidence from someone who produces a report which delves into areas s/he is simply not expert in (medical causation, collision reconstruction) in order to provide a view on what effectiveness a helmet may have had.

So that is why it is not possible to answer this question by simply recommending an expert.

If you are forced into a position where you must get evidence on the efficacy of a bicycle helmet in order to protect the Claimant’s damages award, you should consider working through a series of experts in the following order:

1. Collision reconstruction. You need to have solid evidence on the speed (and crucially closing speed) of the head’s collision with any particular surface, as well as where the impact occurred to the head, from what direction etc. in which an analysis of the damage to the helmet will be of great benefit. There are a number of excellent experts in this field.

2. Materials/product analysis expert. This could well be a joint report with the collision reconstruction expert. It is helpful if this expert has good knowledge of cycling helmets, but a very good expert in materials should be able to analyse how a product is designed and how it functions.

Really what they need to focus on is the structure, materials and safety standards of a helmet and its capabilities and limitations. They must liaise with the reconstruction expert’s findings in order for a calculation to be provided between them as to the forces going through the helmet in the particular circumstances in order to establish the efficacy or otherwise of the helmet in preventing those forces in getting to the head. That information can then be provided to the expert in medical causation to facilitate a better-informed view on whether a helmet has been capable of limiting the damage sustained;

3. Neurology evidence from a Consultant Neurologist or Neurosurgeon with a specific expertise in brain injuries. I don’t think it matters too much who you go to - the expert is not giving evidence on his/her own as to whether a helmet would have offered sufficient protection to prevent the injury (they can’t do that in isolation as they are not qualified in materials/product analysis). At the outset of any cycling case with a significant brain injury however you should bear this potential complication in mind when selecting your condition and prognosis expert, to save doubling up on neurology;

4. Neuroradiology (this discipline may be used in addition to the neurologist to really drill down on the mechanics of the injury if needed – looking at evidence of structural damage to the brain as a result of particular insult(s). Enhanced 3t MRI scans have brought this science significantly forward in recent years.

In summary, it is not so much who you go to, but making sure (by convincing the Judge at the Directions Hearing) that for the matter to be dealt with safely:

a. Sequential exchange is the most appropriate form of case management;

b. A combined expertise is necessary in at least 3 disciplines; and

c. The provision of that expertise should occur in a structured order – reconstruction, materials, medical causation.

The Claimant is likely to face opposition on obtaining this level of expertise at significant expense. It is important to bear in mind and make the Court aware though, that the area is complex and often in serious cases even the loss of 25, 15 or even 10% of the damages award will have a very significant impact on the Claimant’s damages outcome.

If the Defendant really wants to run this Defence in brain injury cases they should be prepared to accept that it will be a necessarily expensive exercise for arguably diminishing returns.