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Notes for UK law enforcement and legal practitioners engaging polygraph services: PCSOT context, the HMPPS statutory regime, evidential weight, and how to instruct a compliant examination.

Polygraph in Law Enforcement and Legal Practice

This page is for UK law enforcement professionals, probation and HMPPS staff, prosecutors, defence practitioners, and other legal professionals who may encounter or commission polygraph examinations.

Statutory Context

Mandatory polygraph testing in England and Wales is administered by HM Prison and Probation Service under:

  1. sections 28 to 30 of the Offender Management Act 2007 (specified sex offenders on licence); and
  2. section 76 of the Domestic Abuse Act 2021 (specified domestic abuse perpetrators on licence).

Outside those statutory contexts, polygraph examinations in the UK are consensual and conducted for investigative, corporate, or private purposes.

Evidential Status

Polygraph results are generally not admitted in UK criminal proceedings. In civil, family, employment, and regulatory contexts, admissibility and weight are matters for the tribunal or court concerned.

Statements made by an offender during a polygraph examination conducted under the statutory licence-condition regime cannot be used as evidence in criminal proceedings against the offender.

Operational Considerations

Where a polygraph examination is considered in an investigative or legal context:

  1. identify the purpose — investigative, evidentiary, screening, or post-conviction;
  2. confirm the lawful basis for the examination (consent or statutory authority);
  3. consider data protection implications under the UK GDPR and the Data Protection Act 2018, and any relevant law enforcement data protection regime;
  4. instruct a BPS-listed examiner with the relevant specialism;
  5. agree the scope of the instruction, the issues to be tested, and the use of the resulting report in writing.

PCSOT Examinations

Post-Conviction Sex Offender Testing (PCSOT) requires specialised training. BPS members conducting PCSOT examinations must hold a certificate evidencing a minimum of 40 hours of specialised PCSOT instruction consistent with APA standards, and must comply with both the BPS Standards of Practice and any policies or contractual obligations imposed by HMPPS.

Using the BPS Directory

The BPS directory identifies examiners who meet the Society’s admission criteria and are bound by its Code of Ethics. Filter by specialism (for example PCSOT, law enforcement, corporate, or private) to match the examiner to the requirement.

Quality Assurance

BPS members are required to document examinations to a standard that allows replication of the analysis and conclusion by a reviewing examiner. The Standards of Practice set out the minimum material that must be retained and produced on a quality-control review.

Complaints

Complaints about a BPS member’s conduct may be made to the Secretary under the Complaints, Discipline and Appeals Procedure. The Society has no statutory or regulatory role; its sanctions operate as between the Society and the member, and do not displace any right to pursue legal or regulatory remedies elsewhere.