Hassan, R v

Expert psychological evidence has no automatic admissibility on an issue of intent. Its relevance depends on the particular issues and facts, and on whether it can assist the jury. It may assist in interpreting conduct which might otherwise suggest a particular motive. It is not admissible merely to speculate about how a defendant’s mind might have operated when the defendant was capable of forming the required intent. Evidence which conflicts with the defence case and would confuse rather than elucidate the jury should be excluded.

The applicant faced trial at the Central Criminal Court for attempted murder and causing an explosion after leaving an improvised explosive device on a London Underground train. He admitted making the device but maintained that it was a hoax deliberately designed not to cause harm.

At a preparatory hearing under the Criminal Procedure and Investigations Act 1996, Haddon-Cave J excluded proposed evidence from a psychologist concerning Asperger’s disorder and its possible bearing on the applicant’s thinking. He also refused permission to appeal.

The applicant sought leave from the Court of Appeal. The central issue was whether the psychological evidence was relevant and admissible on the question of intent.

1. Leave to appeal was refused. The proposed evidence was served very late, but the decisive point was that it was inadmissible in law and inconsistent with the defence case.

2. The court rejected any supposed general rule that psychological evidence is admissible, or inadmissible, on an issue of intent. The proper question is whether, on the particular facts and issues, the material can assist the jury. Expert evidence may assist the interpretation of conduct where a developmental disorder could give conduct a meaning different from that which it might otherwise bear.

3. That did not permit a psychologist to assist the jury in deciding what the applicant actually intended when making and deploying the device. The applicant did not contend that he lacked capacity to form the requisite intent. The proposed reports did not establish his actual intention. They advanced only a speculative and qualified account of how his mind might have operated.

4. The reports also conflicted with the defence case. The defence asserted that the applicant deliberately used weaker chemicals and modified the device to prevent an explosion. The psychological account instead suggested that he may not have understood the risk of harm. Those accounts could not coherently be advanced together. The evidence would confuse the jury rather than elucidate the issue of intent.

5. The court therefore upheld the exclusion of the evidence and the refusal of permission to appeal under the Criminal Procedure and Investigations Act 1996.

• Court of Appeal (Criminal Division): refused the applicant leave to appeal in [2018] EWCA Crim 498.
• Central Criminal Court: at a preparatory hearing, Haddon-Cave J excluded the proposed psychological evidence and refused permission to appeal. No citation for that ruling was stated.