HM Government has confirmed a further extension of polygraph testing within the criminal justice system, widening the circumstances in which a polygraph licence condition may be imposed on certain offenders released into the community. The development has implications for probation practitioners, solicitors, barristers, and safeguarding professionals.
The policy direction is clear: polygraph testing is not being treated as a standalone proof of guilt or innocence. Instead, it is being positioned as an additional risk-management tool for probation practitioners supervising individuals who may present a serious risk of harm.
According to Government materials linked to the Crime and Policing legislation, the Probation Service has used polygraph testing with people convicted of sexual offences since 2014, and with people convicted of terrorist or terrorist-connected offences since 2021. The Ministry of Justice impact assessment states that more than 9,000 polygraph tests have been carried out since 2014.
What Is Changing?
The Government's policy position is to extend polygraph testing to further categories of offender where it is considered necessary for public protection and risk management.
The proposed extension applies to certain individuals, including:
- Those convicted of murder and assessed as posing a risk of committing a sexual offence on release.
- Those convicted of concurrent sexual and non-sexual offences, where the sentence for the sexual offence expires before release for the non-sexual offence.
- Those convicted of a non-terrorism offence with a terrorism connection, or where the Secretary of State is satisfied that the offence took place in the course of terrorism or was committed for terrorist purposes.
The Government also refers to historic terrorist-connected offenders, including provisions that may enable specific counter-terrorism risk-management tools to be applied to a small number of historic offenders.
Polygraph Testing Does Not Replace Professional Risk Assessment
One of the most important points to understand is that polygraph testing does not replace existing offender management processes.
It is used alongside professional judgement, licence supervision, MAPPA processes, intelligence gathering, treatment work, safeguarding procedures, and other risk-assessment tools. The Government's own language is clear: polygraph testing provides probation practitioners with additional risk-related information that they may not otherwise have known.
That distinction matters.
A polygraph examination is not simply about whether a person 'passes' or 'fails'. In properly conducted post-conviction testing, the value often lies in the disclosures made before, during, or after the examination, and in how those disclosures inform supervision, safeguarding, and risk-management decisions.
What Does a 'Significant Response' Mean?
In Government and Probation Service language, a 'failed' polygraph test is more accurately described as a significant response. This means that the physiological data indicate deception in response to one or more relevant questions.
The Probation Service policy framework identifies possible outcomes as:
- Significant Response — deception indicated.
- No Significant Response — deception not indicated.
- Inconclusive — no reliable decision can be reached.
- No Opinion — the data cannot be scored reliably.
A significant response does not automatically prove further offending. However, it may cause probation practitioners to reassess risk, increase reporting requirements, vary licence conditions, change supervision priorities, refer information to other agencies, or consider whether the person can continue to be safely managed in the community.
The Probation Service policy framework is also clear that the result of a polygraph examination cannot itself be used as the basis of recall. However, disclosures made during the process, or risk-related information arising from the examination, may contribute to further investigation, safeguarding action, or recall where appropriate.
Why This Matters for Public Protection
The central policy rationale is public protection.
The objective is to strengthen risk management for those on licence who pose the greatest risk of sexual harm, reoffending, or terrorism-related harm.
In practice, polygraph testing can support offender management by:
- encouraging fuller disclosure;
- identifying hidden risk behaviour;
- testing compliance with licence conditions;
- helping practitioners prioritise supervision;
- supporting multi-agency safeguarding decisions;
- providing a structured interview process around risk-relevant behaviour.
This is particularly important in cases where risk may be dynamic, concealed, or difficult to monitor through ordinary supervision alone.
A Measured but Significant Expansion
The extension of polygraph testing should not be misunderstood as a move towards using lie detectors as courtroom evidence.
Instead, the direction of travel is towards structured risk management.
Polygraph testing is being embedded as a specialist tool within licence supervision, particularly where public protection concerns are high and where undisclosed behaviour could materially affect risk.
For solicitors, barristers, probation professionals, and investigative practitioners, the key point is that polygraph testing is increasingly recognised within statutory and operational frameworks — but its use remains bounded by legal criteria, professional standards, proportionality, and safeguards.
Professional Reflection from Dr Keith Ashcroft
“The Government's continued extension of polygraph testing reflects a broader recognition of its value when used carefully, ethically, and within a defined risk-management framework. Polygraph testing should never be presented as infallible. Nor should it be used casually, coercively, or outside proper professional boundaries. Its value lies in structured questioning, careful preparation, validated procedures, skilled interviewing, and appropriate interpretation of results. When used properly, polygraph testing can help uncover information that may otherwise remain hidden. In high-risk cases, that information can materially assist those responsible for public protection, supervision, and safeguarding. The latest Government position reinforces what many practitioners already understand: polygraph testing is not a substitute for professional judgement, but it can be a powerful adjunct to it.”
Instruction and Professional Referral
Solicitors, barristers, and professional referrers requiring independent polygraph services can contact the Centre for Forensic Neuroscience to discuss suitability, scope of instruction, and the appropriate formulation of test issues.
Initial enquiries are handled confidentially. All examinations are conducted in accordance with APA (American Polygraph Association) standards of practice and are subject to professional and ethical safeguards.
Important Disclaimer
This article is provided for general educational and professional information only. It does not constitute legal advice. Polygraph testing is not proof of guilt or innocence. It is an additional risk-management tool and does not replace professional judgement, MAPPA, probation supervision, safeguarding, or other risk-assessment processes. Policy and legislative references are based on publicly available Government materials at the time of writing and should be verified independently. No solicitor-client relationship is created by this publication.
Dr Keith Ashcroft is an Investigative Psychologist and Polygraph Examiner at the Centre for Forensic Neuroscience. The Centre provides polygraph examinations, investigative psychology, and forensic consultation for legal, corporate, and private clients. For professional enquiries, please contact us to discuss your requirements in confidence.