Court warns of witness coaching by AI

Witness coaching v witness familiarisation

In R v FGD, an appeal from the Crown Court in a jury trial, the Court of Appeal considered whether the judge had been correct to stay the proceedings as an abuse of process where the complainant had used AI to prepare to give evidence.

Witness coaching is strictly forbidden in English proceedings, both criminal and civil. That is to be distinguished from witness familiarisation, where a witness is taught about the process in advance and advised on how to give their evidence effectively. The key difference between the two is that witness familiarisation must take place in the abstract, not involving any reference to the facts of the case the witness will appear in. It can involve a mock cross-examination, but without reference to the witness’s actual evidence.

This distinction was highlighted in the 2005 case of R v Momodou, where it was discovered that key witnesses had received training using a hypothetical case study that was very close to the facts of the real case. The Court was highly critical of what had taken place. That the same principles apply in civil cases was confirmed in Ultraframe v Fielding.

“Suggested answers”

In R v FGD, the prosecution in a rape trial was ordered to disclose the entire contents of the complainant's phone after she referred to screenshots of where she and the defendant had been. When the download was reviewed, it revealed that she had consulted an AI tool to prepare for her cross-examination.

The AI summarised the task: “What I am going to do first is pull together everything you've shared about that night into one clear picture, so that you can see how strong and consistent your account actually is. Then I'll go through every question a defence lawyer might ask with suggested answers.” There followed several pages of text and “24 highly pertinent questions and suggested answers”.

The judge in the Crown Court acceded to an application by the defence to stay the proceedings as an abuse of process. On appeal, the Court of Appeal was clear that what had occurred was witness coaching – the fact that it was by software rather than a person did not affect the nature of the exercise.

However, on the facts of the case, the Court held that a stay was not required. The complainant’s evidence in chief had been recorded before she consulted the AI tool, so only her evidence in cross-examination was tainted. There was other evidence in the form of contemporaneous text messages for the jury to consider and the jury could reach its own view on the reliability of her evidence in cross-examination with the knowledge that she had used the AI tool. The case was remitted back to the Crown Court for a re-trial. In expressing concern about what had occurred, it noted that this was “unlikely to be an isolated example”.

Wider implications

Although the way evidence is given differs in civil trials and in criminal ones, with the use of written statements as evidence in chief in civil trials, the rules on witness coaching are the same. There is thus a real risk of witnesses acting on their own volition in preparation for trial and seeking assistance from AI, without realising they are breaking the court’s rules. Cross-examining counsel are likely to start asking about this when a witness is performing well. Questions about professional witness familiarisation are already sometimes asked, in the hope of making the judge wary of an overly polished performance.

As interactions with a public AI tool cannot be privileged, as they lack the necessary quality of confidentiality, any interactions between a witness and an AI tool may even fall to be disclosed under the continuing duty of disclosure. The courts are already familiar with ordering the disclosure of chat logs with AI tools.

If a witness is found to have used AI to coach them for cross-examination, the judge is likely to either exclude their evidence entirely or accord it far less weight than would otherwise be the case. This could fatally undermine that party’s case. Witnesses should therefore be warned against using any AI tools to help them prepare for their day in court. If they are nervous about the process and have no prior experience, witness familiarisation can be offered, but this should be supervised by a solicitor or barrister and none of those involved should have personal knowledge of the matters in issue, as prescribed by R v Momodou.