AM, R v

Expert psychological evidence concerning an accused’s suggestibility, compliance and vulnerability to influence is not admissible merely because it describes the relationship with a co-accused. It must be material to an issue the jury must decide. Where the defence is that the accused did not believe the co-accused was serious and did not commit any preparatory act, such evidence does not assist unless it bears on that defence or the prosecution case. Its relevance may differ where duress or the reliability of a confession is in issue.

The applicant was convicted at the Central Criminal Court of engaging in conduct in preparation for terrorist acts, contrary to section 5(1)(a) of the Terrorism Act 2006.

The prosecution relied on covertly recorded conversations, alleged assistance with planning an attack, and evidence said to show support for Islamist extremism. The applicant accepted the conversations but maintained that he believed his co-accused was merely talking and that he had not intended to assist any terrorist act.

During the trial, the judge excluded proposed evidence from two forensic psychologists concerning the applicant’s suggestibility, compliance and vulnerability to manipulation. On a renewed application for leave to appeal against conviction, the central issue was whether that evidence was relevant to a matter the jury had to determine.

1. The renewed application for leave to appeal against conviction was refused.

2. The court held that the proposed psychological evidence was not relevant to the issues at trial. The applicant’s defence was not that he had performed preparatory acts under the influence of his co-accused. Rather, he denied taking the discussions seriously and denied intending to assist terrorist acts.

3. The jury had to determine whether the co-accused genuinely intended terrorist acts and, if so, whether the applicant assisted him and shared that intention. Evidence that the applicant was compliant, suggestible or vulnerable to manipulation did not bear on either the prosecution case or the defence actually advanced.

4. There was no issue of duress and the prosecution relied on no confession whose reliability could have made suggestibility material. The trial judge’s alternative reliance on the line of authority culminating in R v Jackson-Mason [2014] EWCA Crim 1993 therefore did not need to be resolved by the court. The absence of relevance was sufficient to reject the appeal.

• Court of Appeal (Criminal Division): The renewed application for leave to appeal against conviction was refused: [2019] EWCA Crim 1705.

• Central Criminal Court: On 2 March 2018, the applicant was convicted of an offence contrary to section 5(1)(a) of the Terrorism Act 2006.