R v BRM & the admissibility of psychiatric evidence: An unfortunate reminder of the importance of detailed and clear instructions to experts

 R v BRM [2022] EWCA Crim 385

The Court of Appeal considered whether evidence of a child’s diagnosis of ASD should have been admitted at trial. The Court reiterated the general rule that expert evidence is only admissible if it is relevant to a live issue in the case.  In this particular case, there was no evidence to suggest that the applicant’s ASD impacted on his ability to form the requisite intent and, although such evidence may have been relevant to the subjective limb of the legal test for self-defence, the expert evidence did not adequately address this point.  


BRM, a 14 year old child, was jointly charged with X for the murder of V. It was the Crown’s case that V had been lured to a location by Y, his former girlfriend. X and BRM, who was in possession of a knife, attended the location where a fight ensued between X and V. During the altercation, V was stabbed twice by BRM. The Crown’s case was that this was a planned attack on V and that BRM attended the location armed with a knife for this purpose.  BRM denied that he was part of any planned attack, stating he was acting in lawful defence of X and that he had no intention to kill V or cause him serious injury. 

BRM had a long-standing diagnosis of Autism Spectrum Disorder (ASD). Two psychiatric reports had been prepared confirming the diagnosis and how it impacted his behaviour. He was assisted throughout the trial by an intermediary, however, the trial judge ruled that the psychiatric evidence was inadmissible on the following basis:

1.    The expert reports failed to comply with Part 19 of the Criminal Procedure Rules;
2.    The psychiatric evidence could not be relevant to the issue of intent; 
3.    Whilst the evidence might be relevant to the subjective element of the test of self-defence, or defence of another, the psychiatric evidence, as served, did not address that issue. 

Both BRM and X were convicted of murder.  

BRM sought leave to appeal his conviction on the basis that the ASD diagnosis and psychiatric evidence should have been admitted; this was relevant to his intent and to the subjective element of self-defence. It was also submitted that the defence should have been permitted to adduce the diagnosis through BRM and that the trial Judge had erred by not granting the defence an adjournment to obtain a further psychiatric report. Leave to appeal was refused by the Single Judge however, the application was renewed before the full Court. 


The Court of Appeal first considered the argument that the defence should have been able to adduce the diagnosis of ASD from BRM. It observed that whilst BRM’s instructions were that he was aware of his diagnosis and how it may affect parts of his behaviour, this was contradicted by the expert report which stated that he had ‘no idea what it actually meant’ .  The Court rejected this, stating that the ASD diagnosis was not relevant to the issues that the jury had to decide. The advocate was permitted to ask questions of the applicant in relation to how he responded to certain stimuli but the ‘the mere fact of the diagnosis took the jury nowhere’ and ‘juries should not be burdened with evidence unless it is probative of an issue in the case’ .

The Court held that there was no suggestion that ASD, as it applied to the applicant, affected his ability to form the requisite intention; that was not how the case was put. The Court considered what the competing factual cases were and determined that the diagnosis was not relevant to either scenario and therefore, the evidence was inadmissible as to the issue of intent in this case . 

The Court however, did accept that the evidence may be admissible as to the subjective limb of self-defence. Nonetheless, the expert evidence in this case did not address how the diagnosis of ASD actually impacted upon BRM’s actions during the course of the fight; the opinion was predicated upon how a person with the applicant’s characteristics would have responded to a generalised fight situation. 

Finally, the Court commented that there was ‘superficial’ force in the argument that the defence should have been granted further time to instruct a different expert. However, the Court again considered the evidence of JBM and determined that “the fact that he had, and still has, Asperger Syndrome (ASD),[…], had no relevance and still has no relevance”. The renewed application was therefore refused. 


On 30 March 2022, the World Health Organization estimated that 1 in 100 children are living with Autism. This, however, represents an average figure with some studies indicating that the number is actually much higher. The way ASD impacts children and young people varies and it is a consideration that those working in the Youth Justice System should always be alive to. 

The Court does not appear to have completely closed the door on such evidence being admissible in criminal proceedings, each case must be judged on its own facts. However, the Court made clear that juries are not to be burdened with evidence unless it is probative of an issue in the case and unless it’s relevance can be clearly and properly understood. It is insufficient for expert evidence to be predicated on how a person with a defendant’s characteristics would have reacted to a generalised situation; it must be clearly linked to the defendant’s actions.  

This case serves as an unfortunate reminder of the importance of  providing clear and detailed instructions to experts, asking experts to amend reports where appropriate or necessary and ensuring that the report complies with Criminal Procedure Rules. 

For guidance on instructing an expert see Instructing an Expert: A toolkit for lawyers and expert witnesses in criminal cases involving children

Written by Sabrina Neves and Greg Stewart, GT Stewart Solicitors