Career
Professor Guðjónsson was a detective with the Reykjavík police before becoming the UK’s leading academic in the psychology of police interviews and confession evidence. His Gudjonsson Suggestibility Scale is the standard instrument used in UK and international forensic practice to assess vulnerability to suggestion during questioning. He was appointed CBE in 2011 for services to clinical psychology.
Work on UK miscarriages of justice
Professor Guðjónsson’s expert evidence has contributed to the overturning of some of the most prominent UK miscarriages of justice of the twentieth century: the Guildford Four, the Birmingham Six, Stefan Kiszko, Judith Ward, Derek Bentley and Sally Clark. The Sally-Clark engagement is particularly relevant here: it places his scholarly framework inside the same evidential family that underlies the post-conviction critique of the Letby case.
Role in the Lucy Letby case
Professor Guðjónsson interviewed Lucy Letby twice over summer 2025 and produced a report for the post-conviction defence team. The report addresses the psychology of the handwritten Post-it-note material found at her home — material the Crown advanced at trial as confessional in nature. His report applies the established literature on self-blame writing by clinicians under sustained institutional accusation, the same framework his career has built across the prior UK appeal record.
The notes themselves oscillate between denial (“I haven’t done anything wrong”, “Why me”) and crushing self-blame on the same page — a pattern the forensic-psychology literature treats as inconsistent with forensic confession, but consistent with the documented stress-response signature in clinicians accused in their professional setting.
Why this biography is on the site
Professor Guðjónsson is among the most senior forensic-psychology authorities engaged publicly with the Letby case. His scholarly framework is the architecture under which any serious reading of the Post-it material now sits. This page exists so readers can navigate to his published work and the analysis pages that apply it.
Read alongside
- Analysis: self-blame psychology
- Analysis: the so-called confessions
- Analysis: PEACE-model interview standards
- Analysis: police interviews critique
- Analysis: Sally Clark parallel
- Sally Clark — biography
Source
King’s College London faculty record; Gudjonsson Suggestibility Scale (Gudjonsson, 1984, 1987, 1997); “The Psychology of Interrogations and Confessions: A Handbook” (Wiley, 2003); public reporting of his Letby case engagement (Rex v Lucy Letby — Full Disclosure, X, August 2025); UK miscarriage-of-justice appellate record.