Caution with Injury Causation: Is the Injury Truly Consistent with the Mechanism?

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A short 5 minute read:

“This injury is consistent with the mechanism described”.

This is a phrase that graces the pages of many a Crown medical expert report in a section 18 assault case.

But what does it actually mean?

Truthfully, very little. That’s why reading this phrase raises the hackles of even the most placid Forensic Pathologist. This reaction slowly fades and is followed by a little chuckle and rubbing their hands together with glee.

Why glee, you might ask? Well, this phrase is a red beacon highlighting a lack of training on the production of a court appropriate report. Forensic experts experienced in working in the criminal justice system know that an expert report must comply with part 19 of the criminal procedure rules (CPR's). It’s pertinent, then, to point out where these reports can fall short of this.


“An expert must help the court to achieve the overriding objective— by giving opinion which is within the expert’s area or areas of expertise” (19.2, 1.a.ii)

Whilst a hospital registrar or consultant is an expert in treating the injury in question, they have not extensively studied the mechanism by which it may have occurred. The causation of injury is therefore not their area of expertise, so presenting an opinion to the causation is stepping outside of that expert’s knowledge set. Despite this, the Crown continue to ask medical consultants to provide an ‘expert’ opinion on causation of injury.


“An expert’s report must give details of any literature or other information which the expert has relied on in making the report; [and] contain a statement setting out the substance of all facts given to the expert which are material to the opinions expressed in the report, or upon which those opinions are based” (19.4, b&c)

We are often asked to review the evidence from a hospital doctor and are then presented with a single page report that frequently contains just one line of opinion. No indication is given as to the material used by them to inform their opinion and no statement to the facts of the case that have allowed them to draw the conclusions that they have made.

In all cases the court should be able to understand what the expert has used to help them formulate their opinion and conclusions. It should be clear from the report how this information has gotten them to their viewpoint. This is not possible in a one line report.


“An expert’s report must contain a summary of the conclusions reached” (19.4, i)

Often the report’s single line is “This injury is consistent with the mechanism described”, and so a summary of the conclusions is not possible.  This means that the report gives the reader no indication as to the likelihood of the injury having been caused by the mechanism alleged. Equally this means that the likelihood that the injury isn’t caused by what the prosecution have alleged isn’t clear either. It details no potential weapons used and gives no indication of the force required in order to cause that injury. All of these aspects of an expert’s conclusions can be crucial in a case where the client's defence is accidental injury for example. These opinions simply are not given and as such the report is of little use to the police, you and your client or the court.


“An expert’s report must contain a statement that the expert understands an expert’s duty to the court, and has complied and will continue to comply with that duty; and contain the same declaration of truth as a witness statement.” (19.4, j&k)

These required passages are notably absent from many of the crown expert reports that we see and are asked to review. Although many of these reports are served on behalf of the crown we urge you as a defence solicitor to be mindful that the expert you instruct includes these necessary statements in their reports. Otherwise there is a very real chance that the judge could refuse to allow the evidence to be used in court.


“Unless the parties otherwise agree or the court directs, a party may not introduce in evidence an expert report if the expert does not give evidence in person.” (19.3, 4b)

As I outlined earlier, many crown experts in cases involving injury causation are hospital doctors, highly trained in the preservation of human life. They are not trained in court presentation skills, may not have participated in numerous trials and their opinions are not subjected to the rigour of cross-examination on a regular basis. For the defence this presents an opportunity.


At Forensic Access we use the expertise of a Forensic Pathologist to comment on how the injuries in the case may have been caused. This is something that Forensic Pathologists study and specialise in and cannot be replicated by non-forensic experts without the necessary training. Their daily casework consists of assessing injuries in the deceased and the living.

In each individual case they use their considerable experience to analyse the information provided to them. And to draw conclusions that can assist the jury in deciding which is the more likely scenario of those presented in court. In cases with no witnesses such as domestic abuse, this expert opinion is invaluable.

All Forensic Access expert reports comply with the criminal procedure rules in terms of their content as we believe it is paramount that such vital information is provided in an appropriate format for court.

The expert Forensic Pathologists we work with have given evidence at hundreds of criminal trials, are well versed in presenting and justifying their opinion when cross-examined. In addition they can provide questions to put to the crown expert and identify areas to challenge in their report over and above what I have laid out here.

I hope this article has given you some points to consider when choosing an expert to provide a mechanism of injury report for use in a criminal trial.


Please direct any questions about its content or any cases you would like to discuss further to You can also contact our casework team here.

For more information around injury causation, and the services we can provide, please take a look at our services page. We've also published a short Q&A with one of our Forensic Pathologists, Dr Stuart Hamilton.You can find this on our news page here.

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