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Safeguarding the Integrity of Expert Witnesses

What can we learn from the Post Office Scandal

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A Short Summary

The UK Post Office media scandal stands as a reminder of the profound consequences that can arise from the misuse of expert witness decisions and reports in legal proceedings. Spanning over a decade, this misconduct unfolded because of system failures within the Post Office’s computerised accounting system. This led to wrongful accusations of theft, fraud, and false accounting of over 900 Post Office staff (Ismay, 2022).

Examining the Power Misuse Severity in the Post Office case-study

Leadership from both companies defended Horizon with such a zealousness that crept down to middle, lower management and eventually front-line staff (Bridgeman & Cummings, 2023).

  • With hierarchical pressure, despite knowledge of the system errors, the staff reluctantly continued to use the system despite its defects.
  • Staff never discussed these issues due to fear of reprimand. With a perfect example being the case of Seema Misra, a sub postmaster who was falsely prosecuted and jailed. And after the wrongful conviction, Jarnail Singh (head of Criminal Law in the Post Office)  released a celebratory email underlining that this example should prevent others from jumping on the “Horizon Bashing Band Wagon” (McCulloch, 2024 & Marshall, 2020).

The Devastating Effects of Expert Witnesses Misuse and Malpractice

This case was further exacerbated by half-truths, misdirection and misuse of expert witnesses, whose testimonies played a pivotal role in facilitating miscarriages of justice.

  • The experts entrusted with providing impartial and objective analysis, were instead co-opted to serve the interests of both the Post Office and Fujitsu, often at the expense of truth and justice.
  • In many instances, expert witnesses failed to disclose conflicts of interest, misrepresented crucial evidence, or provided testimony that lacked credibility and integrity.
  • The intentional misleading of the justice system in cases such as in the case of Lee Castleton who was penalised with £25,000 primarily due to a false EW testimony (Wallis, 2021 & Marshal, 2021).

However, amidst the fallout of this scandal, there are many critical lessons to be learned to allow us to better safeguard the integrity of Expert Witnesses.


The Much Needed Reform. Your Opportunity To Join Psychology Direct. Our Clients’ Stamp Of Integrity

To prevent the repeat of such injustices, it is imperative to implement robust processes and procedures for ensuring the integrity of our Expert Witnesses. First and foremost, there must be greater transparency and accountability in the selection and appointment of expert witnesses.

  • With our foolproof process, every client enquiry is provided with a specifically curated range of Experts to choose from. And with  over 1000 active experts we ensure that there is NO active or potential conflict for our experts.
  • Our experts are thoroughly vetted and pre-approved by Psychology Direct.
  • All our EW assessments are reviewed internally to ensure grammar, clarity, non-bias and accuracy.

As further underlined by the MOJ (Ministry of Justice, 2020), we uphold the highest ethical guideline, and all our EWs are advocates of the highest standards of professionalism and integrity, mitigating the risk of bias by ensuring that decision-making is always in line with 3 key principles (Lubet, & Boals, 2020):

  • Sufficient Facts and Data
  • Reliable principles and methodologies
  • Direct and complete application of set principles and methodologies

Final Remarks

In spite of the challenges caused by the Post Office case study which are still perceptible, we are at the forefront of advocating the insurmountable importance of expert witnesses in the pursuit of justice and truth.

When utilised ethically and responsibly, Expert Witness testimonies and Reports provide invaluable insights that often shape the outcome of legal proceedings. And the UK Post Office scandal serves as a true reminder of the dangers of misusing expert witness reports and testimonies in legal proceedings.

By joining Psychology Direct, our experts can stand true to their values of impartiality with ZERO conflict of interest, not even the financial remuneration.

And our clients can be sure of no negative conflict of interest, with the unique opportunity of having a pool of pre-vetted and highly experienced experts to choose from, even when a case requires experts with highly specialised skills and knowledge.





Bridgman, T., & Cummings, S. (2023). How ideology shapes what we teach about authority: A comparative analysis of the presentation of Milgram’s experiments in textbooks. Academy of Management Learning & Education22(2), 293-311

Growns, B., Kukucka, J., Moorhead, R., & Helm, R. K. (2024). The Post Office Scandal in the United Kingdom: Mental health and social experiences of wrongly convicted and wrongly accused individuals. Legal and Criminological Psychology29(1), 17-31.

Ismay, R. (2022). Ismay Report: Horizon-Response to Challenges regarding Systems Integrity (Post Office Limited, 2 August 2010). Digital Evidence & Elec. Signature L. Rev.19, 1.

Lubet, S., & Boals, E. I. (2020). Expert testimony: A guide for expert witnesses and the lawyers who examine them. Aspen Publishing.

Marshall, P. (2020). The Harm That Judges Do-Misunderstanding Computer Evidence: Mr Castleton’s Story’an Affront to the Public Conscience’. Digital Evidence & Elec. Signature L. Rev.17, 25.

McCulloch, A. (2024). Groupthink, obedience, dishonesty: The Psychology of the Post Office Scandal. Personnel Today

Ministry of Justice. (2020) Civil Procedure Rules.

Moorhead, R., Nokes, K., & Helm, R. (2021). Post office scandal project: issues arising in the conduct of the bates litigation. Available at SSRN 3894944.

Pilgrim, D. (Ed.). (2023). British Psychology in Crisis: A Case Study in Organisational Dysfunction. Phoenix Publishing House.

Wallis, N. (2021). The Great Post Office Scandal: The Fight to Expose A Multimillion Pound Scandal Which Put Innocent People in Jail. Bath Publishing Limited.