Oral evidence series Part 6: Is an honest recollection of events truly evidence?

Judicial commentary shows that judges are exceedingly aware of the unreliability of witnesses’ memory when considering evidence at trial. While judges may take differing views as to the reliance that ought to be placed on oral evidence as compared to contemporaneous documents, procedural safeguards are now in place to help strengthen the reliability of witness evidence, in CPR Practice Direction 57AC - Trial Witness Statements in the Business and Property Courts (“PD 57AC”).
 

Witness memory and judicial commentary
 

In litigation, judges may be faced with two witnesses who give different accounts of the same events, while at the same time both believing that the evidence they give is accurate. This has led to the idea that there can be at least three sides to every story: yours, mine, and the truth. Memory is not perfect, and science has shown that through the process of recalling events, an individual can change or edit their own recollection.

In fact, as discussed in case law, the process of litigation itself may facilitate this rewriting of memory. In Gestmin SGPS SA v Credit Suisse (UK) Ltd Leggatt J remarked that litigation “subjects the memories of witnesses to powerful biases”, including how a witness’s memory is “refreshed” by reading contemporaneous documents in advance of drafting a witness statement. This is not a new observation. Nearly 50 years before Gestmin, the House of Lords in Onassis v Vergottis in 1968 had considered credibility and reliability of witnesses, with Lord Pearce summarising the numerous considerations taken into account when assessing witness credibility, such as whether the witness’s recollection has been “altered by unconscious bias” during the course of the litigation.

The judicial commentary from Gestmin and Onassis highlights the reality that memory is fundamentally unreliable. The suggestion proposed is that judges should instead rely on contemporaneous documents - a sentiment that has been repeated in multiple judgments since, including by Lord Justice Males in 2019 in Simetra Global Assets Ltd and another company v Ikon Finance Ltd and others. In Simetra, Lord Justice Males remarked that contemporaneous documents are “far more reliable than the oral evidence of witnesses”.

Procedural changes
 

Against the backdrop of such judicial criticism on the unreliability of witness evidence, Practice Direction 57AC was introduced in 2021. This implemented a process of record-keeping to encourage compliance with the rules around the preparation of trial witness statements.

Incorporating what became known as the ‘Gestmin principles’ into the appendix of the practice direction, it was hoped that, by tightening up the rules around how written evidence was taken from witnesses, it would help limit the reconstruction of memory discussed in Gestmin and re-instil witness credibility in the minds of judges.

Appendix to PD 57AC

“Witnesses of fact and those assisting them to provide a trial witness statement should understand that when assessing witness evidence the approach of the court is that human memory:

1. is not a simple mental record of a witnessed event that is fixed at the time of experience and fades over time, but
2. is a fluid and malleable state of perception concerning an individual’s past experiences, and therefore
3. is vulnerable to being altered by a range of influences, such that the individual may or may not be conscious of the alteration.”

A year and a half after these procedural changes were brought in, Lord Justice Popplewell gave an interesting speech to the Commercial Bar Association. He concluded that “generally human memory is remarkably accurate and recollection is a very valuable tool in determining what happened and why it happened… the pendulum may have swung too far in the direction of dismissing memory as a useful and reliable tool in court”.

Jackman v Harold Firth & Son Ltd

This case is interesting as the judge considered several authorities that “highlight the danger of treating honest recollection of events that happened a long time ago as firm evidence”.

After his death, Mr Jackman’s medical evidence revealed a possible cancer of the lining of the lung which could have been as a result of asbestos exposure. His widow brought a civil claim against Mr Jackson’s former employer, where he had allegedly worked almost 50 years before his death.

Mrs Jackman and two other workers gave evidence regarding the working practices at the Defendant company. At trial, the Defendant made submissions about the fallibility of witness memory, relying on judicial comments made in Bannister v Freemans, specifically that the court ought to consider that:

1. “A strong recollection of events expressed with confidence is not a reliable guide to the accuracy of the recollection;
2. The fact a witness has a considerable amount to gain if their recollection of events is accepted by the court as fact means that the witness’ recollection is very likely to be biased towards that which supports the outcome [they seek];
3. When a witness recalls events from the past, [they are] unconsciously reconstructing those events. The description the witness provides of the relevant event or events is in fact a description of the reconstruction undertaken at that point; and
4. Testing recollection against contemporaneous documentation is a very useful and important exercise. Testing in this way at least gives the court an opportunity to compare a near contemporaneous version of events (subject to no or little reconstruction) with a re-constructed version of events.”

The Judge in Jackman also referred to the guidance in PD 57AC on the fallibility of human memory, noting that Mrs Jackman’s witness evidence ‘must be looked at in context and as part of the entire evidential picture…’. Despite this, the Judge found Mrs Jackman’s evidence to be “honest and impressive”. The Judge decided that the Defendant was in breach of the duty owed to Mr Jackman and that breach caused him to suffer personal injury.

Conclusion
 

Despite substantial judicial commentary on the reliability of memory, witnesses will necessarily remain a primary source of evidence in litigation. At trial, the judiciary must consider the inherent fallibility of memory, and the weight that should be placed on contemporaneous documents against witness evidence, when determining the outcome of a case.

About the authors

Laurence is a senior associate in the Dispute Resolution Team. He has been recognised as a leading associate in both commercial litigation and civil fraud in The Legal 500.

Isabella McDonnell is a trainee solicitor at Kingsley Napley and is currently in her second seat with the Dispute Resolution team.