Sexual Offence
Polygraph Tests
Information. Verification. Credibility.
Polygraph examinations can provide highly valuable information in criminal investigations, including cases involving alleged sexual offenses. While test results are probabilistic and are not admissible as primary evidence in UK courts, they continue to offer significant strategic benefits when used effectively as a tool for defence lawyers.
Benefits to Defendants
Strategic Tools for Defence Lawyers
Used properly, modern polygraph examinations assist legal counsel by adding layers of verification, streamlining investigations, and preparing defendants for strict scrutiny.
Honesty Verifcation
If a suspect maintains their innocence, a polygraph test provides an additional layer of confidence for the defence team in verifying this claim.
Identifying Inquiry Areas
Specific stress responses can help defence lawyers accurately determine which areas to investigate further and focus their exploratory efforts on.
Negotiations & Plea Bargains
Passing a polygraph might assist lawyers during prosecutor negotiations, potentially facilitating more favourable plea bargains or lesser charges.
Preparation for Trial
Answering intense questions during a test mirrors trial conditions, helping attorneys prepare their clients' reactions for cross-examination.
Supporting Evidence
While inadmissible alone, test results offer vital supportive information that correctly aligns with and corroborates other pieces of evidence.
Establishing Credibility
Willingly undergoing scrutiny builds a subject's credibility, which proves extremely useful in common "he said, she said" sexual offense scenarios.
Public Perception
If the suspect is high-profile or if public media attention is a factor, passing a polygraph can highly influence broader public perception, regardless of distinct court admissibility constraints.
State-of-the-Art Analysis
Our data analysis is acquired through modern, high-precision instrumentation designed explicitly for forensic psychophysiology.
Limestone Paragon System
We utilise accepted protocols following the APA and ASTM International standards. Utilizing the Limestone Paragon Acquisition System, we benefit from high resolution 24-bit Analog to Digital conversion for superior recordings.
Physiological Proxies
Simultaneous recordings track cardiovascular activity (heart rate, blood pressure, oxygen levels), respiration (thoracic and diaphragmatic breathing), and skin conductance (sweat gland activity) as a function of truth-telling.
A Structured Interview
Tests take between one half to three hours, comprising a detailed pre-test interview, the examination featuring targeted "yes/no" answers, and a thorough post-test debriefing to accurately evaluate the charts.
Expert Witness Evidence
Dr Keith R Ashcroft
BA, MSc, PhD(Edin), C Psychol, CSd, AFBPsS
Dr. Ashcroft is a Chartered Psychologist and Chartered Scientist with a robust academic and research background. His academic portfolio includes graduation from University College Cardiff, Manchester University Medical School, and Edinburgh University Medical School - Forensic Medicine Unit (where he conducted doctoral research directly on neuropsychological impairment in convicted sexual offenders).
He is regularly instructed to provide independent psychological reports in civil and criminal cases, giving expert witness evidence in the High Court of Justiciary throughout Scotland, The Royal Court of Jersey, and across the United Kingdom.
- school British Polygraph Academy Graduate
- gavel Instructed by UK Crown Prosecution Service (CPS)
- badge Member of the American & National Polygraph Associations