How Much Does a Lie Detector Test Cost in the UK?

Our UK Prices

A standard lie detector test with LieDetectorTest.com in the United Kingdom is £595. That is the same price at all 125 of our UK testing offices, from London and the West Midlands to Scotland, Wales and Northern Ireland — there is no London premium and no surcharge for testing outside the major cities.

The fee is all inclusive. It covers the pre-test assessment, the examination itself, numerical scoring of the charts, your verbal result on the day and a full written report. Nothing is added afterwards for the report, for a sensitive subject, or for attending one of our offices.

UK Price List

What the Fee Includes

• The pre-test assessment. A private interview in which your examiner reviews your case and agrees the exact wording of every question with you before anything is recorded.
• The examination. Multiple chart collections run by an examiner trained to APA and British Polygraph Society standards, using validated techniques.
• Numerical scoring. The charts are scored after the test, not judged on the spot.
• Your result on the day, explained to you verbally before you leave.
• A full written report within 48 hours, setting out the questions asked, the technique used and the conclusion.
• A private, appointment-only office within a reasonable distance of most mainland addresses.

Where You Can Be Tested

We hold appointments at 125 controlled testing offices across 43 UK counties and regions, including London, Greater Manchester, the West Midlands, Kent, West and North Yorkshire, Merseyside, Staffordshire, Scotland, Wales and Northern Ireland. Because the price is the same everywhere, choosing an office is purely a question of what is convenient for you.

Prices on this page are for testing booked through LieDetectorTest.com and are shown in pounds sterling.

Book a UK lie detector test → See every UK testing office →

Examiner Qualifications and Experience

The expertise and accreditation of your polygraph examiner is the single most important factor influencing both price and reliability. According to the British Polygraph Society, BPS examiners complete hundreds of hours of coursework and commit to ongoing professional development and peer review [2]Verified British Polygraph Society — About
Confirms BPS examiners complete hundreds of hours of coursework with ongoing peer review and professional development. Professionals with extensive experience and a proven track record may charge more for their services [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing.

Examiners with law enforcement or security backgrounds typically charge a premium rate because of their specialised expertise and credibility. The American Polygraph Association (APA) is the gold standard for accreditation worldwide, with over 2,800 members [3]Verified UK Polygraph Associations
Confirms APA has 2,800 members worldwide and is the gold standard for polygraph accreditation. The British Polygraph Society (BPS) upholds the same standards as the APA and serves as the UK's leading professional body for professional polygraph examiners [2]Verified British Polygraph Society — About
Confirms BPS examiners complete hundreds of hours of coursework with ongoing peer review and professional development. When selecting an examiner, always verify their APA, BPS, or BEPA (British and European Polygraph Association) membership [4]Verified British & European Polygraph Association (BEPA)
Confirms BEPA membership requires hundreds of hours of coursework at APA-accredited schools plus ongoing education. For guidance on this critical decision, see our guide to choosing a polygraph examiner in the UK.

Location and Travel Requirements

The cost of a polygraph test varies depending on where the examination is conducted [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing. Most providers maintain controlled office locations across the UK — covering the South East, South West, East of England, East Midlands, West Midlands, Yorkshire, North East, North West, Greater London, Scotland, Wales, and Northern Ireland.

Base office locations typically offer the best rates, while tests at external controlled offices cost slightly more to cover venue hire. If you require a home-based or residential test, providers will need a quiet, noise-free environment with a table, two chairs, and access to a power outlet [5]Verified Terms and Conditions — Lie Detector Test U.K. Services
Confirms residential testing requirements and cancellation policies for UK polygraph providers. Tests in Scotland and Northern Ireland may incur additional transport costs due to the limited number of examiners based permanently in those regions. To find your nearest testing location, visit our polygraph test locations page.

Complexity and Number of Issues

The complexity and scope of the examination can also influence the price [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing. Tests for legal or forensic purposes may be more costly than those conducted for private or personal reasons [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing. More questions typically require more time, which can increase fees [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing.

Standard polygraph testing models allow for a limited number of relevant questions — typically three — about a specific issue. Single-facet tests focus on one specific question, while multi-facet tests can address related aspects of the same issue. If your case requires addressing more than one issue, you may need to book a second test, though providers often offer a discount for additional tests. Some providers also offer expert witness testimony at an additional fee, which can be important for solicitors using polygraph in legal proceedings [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing.

Direct Booking vs. Third-Party Referral

How you book your test can significantly affect the price. However, if the test is booked through a third party such as a private investigator or solicitor, the price may be higher because the intermediary adds their own markup.

Referral agencies often charge more than independent examiners with their own in-house team. If you are quoted a price through a third party that seems excessive, there is nothing stopping you from researching and booking directly with a reputable provider. For more information about when and why people choose private polygraph testing, visit our guide on private lie detector tests in the UK.

The Complete Examination Process

A professional lie detector test is a comprehensive process that lasts approximately two hours. According to the American Polygraph Association, a typical polygraph examination includes three key phases: a pre-test interview, a chart collection phase, and a test data analysis phase [6]Verified Polygraph Frequently Asked Questions
Confirms the three phases of a typical polygraph examination: pre-test interview, chart collection, and test data analysis.

During the pre-test interview, the examiner completes required paperwork, discusses the test with the examinee, answers any questions, and reviews the test questions to ensure the examinee is fully familiar with the procedure [6]Verified Polygraph Frequently Asked Questions
Confirms the three phases of a typical polygraph examination: pre-test interview, chart collection, and test data analysis. This phase is vital for establishing rapport and ensuring the examinee understands every question that will be asked — there are no surprise or trick questions [6]Verified Polygraph Frequently Asked Questions
Confirms the three phases of a typical polygraph examination: pre-test interview, chart collection, and test data analysis. The chart collection phase involves the actual polygraph examination where physiological responses — including blood pressure, respiration, pulse, and skin conductivity — are recorded as the examinee answers a series of targeted questions [7]Verified The Polygraph Test: Overview
Confirms polygraph measures blood pressure, pulse, respiration, and skin conductivity during examination. Finally, the examiner analyses the charts and renders an opinion as to the truthfulness of the examinee [6]Verified Polygraph Frequently Asked Questions
Confirms the three phases of a typical polygraph examination: pre-test interview, chart collection, and test data analysis.

Research confirms that preparation and expertise are critical to accurate results. Studies on the cognitive processes behind deception have shown that lying produces measurable physiological and cognitive costs — for instance, research by Van Bockstaele et al. (2012) found that frequent liars showed a 53 ms lie-effect compared to 239 ms for frequent truth-tellers, though these training effects did not generalise to unpractised scenarios [8]Verified Learning to Lie: Effects of Practice on the Cognitive Cost of Lying
Confirms frequent liars showed a 53 ms lie-effect compared to 239 ms for truth-tellers, but training effects did not generalise.

What Your Fee Should Cover

When you pay for a private lie detector test in the UK, the fee typically covers an overall service — not just the polygraph examination itself. A reputable all-inclusive price should cover:

Pre-examination assessment and case review, where the examiner studies your case details and formulates relevant questions. A comprehensive pre-test interview lasting 30 minutes to an hour. The polygraph examination conducted using state-of-the-art computerised equipment. Post-test analysis using validated scoring methods. A full written report provided on the same day or shortly after. Verbal results communicated to the client on the day of the examination where possible [5]Verified Terms and Conditions — Lie Detector Test U.K. Services
Confirms residential testing requirements and cancellation policies for UK polygraph providers.

The price includes the services of a highly qualified, APA and BPS professional polygraph examiner with qualifications in forensic psychology, criminology, or related fields. Always confirm that the quoted price is all-inclusive with no hidden fees before booking.

Non-Refundable Booking Deposits

This deposit is deducted from the total cost of the test, with the remaining balance payable before or on the day of the examination.

The deposit serves several important purposes. It confirms the client's commitment to the scheduled appointment and covers essential administrative costs, including securing preferred time slots, conducting pre-examination assessments, and assigning a qualified polygraph examiner. Polygraph examiners often have busy schedules and the deposit ensures that their time and resources are properly allocated [9]Verified How Much Does a Lie Detector Test Cost in the UK?
Confirms the purpose and justification of non-refundable deposits and explains examiner preparation costs. Without this commitment, no-shows would waste appointment slots and deny service to other genuinely interested clients [9]Verified How Much Does a Lie Detector Test Cost in the UK?
Confirms the purpose and justification of non-refundable deposits and explains examiner preparation costs.

Payment methods typically include bank transfers, credit cards, and other digital payment options[9]Verified How Much Does a Lie Detector Test Cost in the UK?
Confirms the purpose and justification of non-refundable deposits and explains examiner preparation costs.

Cancellation Terms to Be Aware Of

Cancellation policies across UK providers are broadly similar. The standard approach requires that cancellations are made at least 48 hours before the scheduled appointment. Cancellations made with less than 48 hours' notice, no-shows, arriving late, or missed appointments for any reason typically incur the full non-refundable test fee.

This policy reflects the reality that polygraph testing requires extensive preparation on the examiner's part, including reviewing case details, formulating questions, and calibrating equipment [9]Verified How Much Does a Lie Detector Test Cost in the UK?
Confirms the purpose and justification of non-refundable deposits and explains examiner preparation costs. Providers often cannot fill a cancelled slot at short notice, resulting in a loss of business. If the provider needs to cancel for any reason on their end, most reputable companies will offer a full refund of any deposit and arrange an alternative appointment.

Proven Accuracy Backed by Research

Modern polygraph examinations deliver impressive accuracy rates that justify the investment. The APA's comprehensive meta-analytic survey examined 38 studies across 32 different samples and 45 experiments, encompassing 11,737 scored results from 3,723 examinations [10]Verified Polygraph Validity Research — Meta-Analytic Survey of Criterion Accuracy
Confirms 89% aggregated decision accuracy for event-specific diagnostic testing across 38 studies and 3,723 examinations. The data showed that event-specific (single issue) diagnostic testing produced an aggregated decision accuracy of 89%, with an estimated inconclusive rate of just 11% [10]Verified Polygraph Validity Research — Meta-Analytic Survey of Criterion Accuracy
Confirms 89% aggregated decision accuracy for event-specific diagnostic testing across 38 studies and 3,723 examinations. Multi-issue techniques achieved 85% accuracy [10]Verified Polygraph Validity Research — Meta-Analytic Survey of Criterion Accuracy
Confirms 89% aggregated decision accuracy for event-specific diagnostic testing across 38 studies and 3,723 examinations.

A 2021 meta-analysis of the Comparison Question Test (CQT) by Honts et al. analysed 138 datasets and found that the CQT can be accurate, that experimental studies are generalisable, and that no publication bias was detected [11]Verified A Comprehensive Meta-Analysis of the Comparison Question Polygraph Test
Confirms CQT can be accurate based on 138 datasets, with no publication bias detected. Studies in controlled settings have shown accuracy rates between 83% and 95% [12]Verified Beyond the Polygraph: Deception Detection and the Autonomic Nervous System
Confirms studies have shown polygraph accuracy rates between 83% and 95% in controlled settings. The BPS requires that polygraph techniques used for investigative testing demonstrate an unweighted average accuracy rate of 80% or greater [2]Verified British Polygraph Society — About
Confirms BPS examiners complete hundreds of hours of coursework with ongoing peer review and professional development.

For anyone dealing with false accusations, these accuracy levels can be life-changing. Our guide on how a UK polygraph test can clear your name explains how many people have used polygraph testing to restore their reputations.

UK Government Confidence in Polygraph Testing

The UK government's expanding use of polygraph testing provides powerful evidence of its value. Polygraph examinations have been used successfully by the Probation Service since 2014 in the management of people convicted of sexual offences who have been released on licence [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures. Since 6 January 2014, over 7,000 tests have taken place with individuals convicted of sexual offences, with two-thirds of those tests resulting in significant disclosures [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures.

The original pilot, covering the East and West Midlands probation regions from 2009, was evaluated by the University of Kent between April 2010 and December 2011 [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures. The evaluation concluded that polygraph testing increased the likelihood that an individual would disclose information relevant to their management, supervision, treatment, or risk assessment [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures. This in turn led to an increase in actions taken by probation practitioners to protect the public from harm [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures.

The Offender Management Act 2007 provides the legislative framework for mandatory polygraph testing of sex offenders released on licence [14]Verified The Polygraph Rules 2009
Confirms the legislative framework for mandatory polygraph testing of sex offenders under the Offender Management Act 2007. In 2021, this was extended to terrorist offenders through the Counter-Terrorism and Sentencing Act 2021, and a three-year pilot for domestic abuse offenders was launched under the Domestic Abuse Act 2021 [15]Verified The Polygraph (Amendment) Rules 2022
Confirms 2021 extension of polygraph testing to terrorist offenders and domestic abuse offenders. The Cambridge Centre for Evidence-Based Policing was commissioned to independently evaluate the domestic abuse pilot [16]Verified UK Government to Run Three-Year Pilot of Mandatory Polygraph Testing for Domestic Abuse Offenders
Confirms three-year domestic abuse polygraph pilot evaluated by Cambridge Centre for Evidence-Based Policing. A 2023 two-year review of polygraph testing of terrorist offenders concluded that polygraph testing was an effective risk management tool [17]Verified Crime and Policing Bill: Overview Impact Assessment
Confirms 2023 review concluded polygraph testing of terrorist offenders was an effective risk management tool. For more about how polygraph is used in the UK criminal justice system, see our guide on PCSOT in the UK.

Real-World Impact and Safeguarding Outcomes

The practical impact of polygraph testing extends beyond statistics. There have been a significant number of cases where information gained through polygraph testing has led to children and vulnerable people being safeguarded [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures. Detective Chief Inspector Jude Holmes of Greater Manchester Police has endorsed the use of polygraph testing, noting that the information gleaned through testing is shared with police under multi-agency public protection arrangements to better manage risk [13]Verified Mandatory Polygraph Tests Factsheet
Confirms over 7,000 polygraph tests on sex offenders since January 2014, with two-thirds resulting in significant disclosures.

In one notable case, an offender denied contact with children during a polygraph examination, but his physiological reactions indicated deception. A subsequent home visit by police found minors present, resulting in immediate recall and safeguarding actions. The child killer Colin Pitchfork was recalled to prison in 2021 partly due to suspicions he had attempted to manipulate polygraph results.

Research into countermeasures — deliberate attempts to defeat polygraph testing — has shown that such attempts can often be detected by experienced examiners. A 2010 study by Tuvia Shurany documented a confirmed case where mental countermeasures were successfully identified and exposed through examination procedures [18]Verified Confirmed Mental Countermeasure Case in Costa Rica
Confirms mental countermeasures can be successfully identified and detected during polygraph examination. For guidance on how polygraph helps in child safeguarding, see our dedicated guide.

Infidelity and Relationship Testing

Infidelity testing is the most common reason people book a private lie detector test in the UK. When suspicion erodes trust in a relationship, a polygraph examination can either reinstate confidence or confirm concerns — either way, both partners gain clarity to make informed decisions about their future. More often than not, the report helps repair relationships rather than destroy them.

Interestingly, polygraph bookings spike seasonally, particularly after summer holidays and the Christmas period, when opportunities for infidelity increase. Our analysis of holiday cheating and seasonal polygraph bookings explores this pattern in detail. For a complete overview, see our infidelity polygraph test UK guide. Therapists are increasingly recommending lie detector tests as part of couples therapy — a trend explored in our article on how therapists recommend polygraph to save marriages.

If your partner has already taken a test but doubts remain, our guide on what to do when your partner passed but you still don't trust offers practical next steps.

Theft, Workplace, and Business Investigations

Workplace theft investigations represent a significant portion of commercial polygraph bookings. Employers across various sectors use polygraph testing to identify dishonest employees, verify innocence, and protect business assets.

Research by Twitchell and Fuller (2019) has explored how to properly evaluate deception detection systems by incorporating base rates and cost into system evaluation, highlighting the importance of understanding the economic value of accurate testing [19]Verified Advancing the Assessment of Automated Deception Detection Systems
Foundational research on evaluating deception detection systems by incorporating base rates and cost. For detailed guidance on employer-led investigations, see our workplace theft investigation guide.

False Accusations, Family Disputes, and Legal Support

Being falsely accused of wrongdoing can be devastating, and polygraph testing offers a powerful tool for proving innocence. In the UK, polygraph results can be voluntarily submitted by a defendant to substantiate claims and provide documentary evidence in legal proceedings. While polygraph results are not currently admissible as standalone evidence in UK criminal courts, they can be valuable for building a case and demonstrating credibility.

Importantly, research has highlighted both the power and the responsibility that comes with polygraph results. The Norfolk Four case documented how false confessions were obtained after individuals were falsely told they had failed polygraph examinations — a cautionary example that underscores why it is essential to work with ethical, qualified examiners who follow established protocols [20]Verified 5 Costs and Consequences of Deception, Coercion, and False Confessions: The Norfolk Four
Confirms dangers of false failure claims in polygraph testing and the importance of ethical examination procedures.

Family disputes, neighbour conflicts, and online dating fraud are also common reasons for booking private polygraph tests. Solicitors increasingly recommend polygraph testing to support their clients' cases — our guide for solicitors explains how law firms are integrating this tool.

Red Flags in Polygraph Pricing

While price is a crucial consideration, it is essential not to compromise on quality and accuracy [1]Verified British Polygraph Society — Standards of Practice
Confirms BPS requires validated techniques with 80% or greater accuracy for investigative testing. Extremely low prices — significantly below £300 — may indicate subpar testing procedures, inexperienced examiners, or outdated equipment. Some companies may have purchased cheaper or lower quality instrumentation that they do not regularly update, which lowers their overhead costs but compromises results.

The UK polygraph industry is currently unregulated, meaning anyone can purchase polygraph equipment and conduct lie detector tests. However, the accuracy of such tests will be questionable if the examiner is not highly trained and qualified.

Key red flags to watch for include: providers who cannot name their examiner before the test, those who refuse to share accreditation details, companies that do not provide written reports, and any provider who charges extra for components that should be included as standard (such as the report or post-test analysis).

Questions to Ask Before Booking

When researching providers after searching for lie detector test cost UK, here are essential questions to ask:

Are your polygraph examiners APA, BPS, or BEPA accredited? Is the quoted price all-inclusive with no hidden fees? What equipment do you use and how often is it updated? What does the service include — pre-test interview, examination, analysis, and report? What is your cancellation policy? Where will the test be conducted — at a controlled office or a residential address? How many relevant questions can be addressed in a single test? How long will the examination take? How and when will the results be delivered?

Adaptability is also a hallmark of quality providers. Research by Tuvia Shurany and Fabiola Chaves (2013) documented how professional examiners successfully adapted polygraph procedures to accommodate a deaf-mute examinee, demonstrating the importance of working with experienced practitioners who can handle unique circumstances [21]Verified Testing a Deaf Mute Examinee in Costa Rica
Confirms polygraph examination procedures can be successfully adapted for examinees with hearing and speech disabilities. For comprehensive guidance, read our full guide on how to choose a polygraph examiner in the UK.

The Current Regulatory Landscape

The UK private polygraph industry is not formally regulated by government, meaning there is no statutory licensing requirement to conduct lie detector tests. This makes it particularly important for consumers to verify examiner credentials independently. The British Polygraph Society provides an independent framework of standards, ethics, and peer review, though membership is voluntary [2]Verified British Polygraph Society — About
Confirms BPS examiners complete hundreds of hours of coursework with ongoing peer review and professional development. The BPS advances forensic psychophysiology through commitment to excellence, scientific integrity, and public protection [2]Verified British Polygraph Society — About
Confirms BPS examiners complete hundreds of hours of coursework with ongoing peer review and professional development.

In the government sector, the Polygraph Rules 2009 established strict standards for polygraph operators working with offenders on licence, including qualification requirements, recording standards, and supervision protocols [14]Verified The Polygraph Rules 2009
Confirms the legislative framework for mandatory polygraph testing of sex offenders under the Offender Management Act 2007. These rules were amended in 2022 to reflect the expansion of polygraph testing to terrorist and domestic abuse offenders [15]Verified The Polygraph (Amendment) Rules 2022
Confirms 2021 extension of polygraph testing to terrorist offenders and domestic abuse offenders. Government polygraph examiners must be qualified probation practitioners who have received polygraph training and passed examinations accredited to APA standards, including Post-Conviction Sex Offender Training (PCSOT) [22]Verified Instructions for Imposing Licence Conditions for Polygraph — HMPPS
Confirms government polygraph examiners must be qualified probation practitioners with APA-accredited PCSOT training.

Polygraph Evidence and UK Courts

It is important to understand that polygraph evidence is not admissible as standalone evidence in UK criminal courts [23]Verified Lie Detector Polygraph Testing — Stone King Solicitors
Confirms lie detector evidence is not admissible in British criminal law but is used in offender management. However, this does not diminish the value of polygraph testing for private individuals. In a UK civil case, an involved party may commission a psychologist to write an opinion based on polygraph results to support the credibility of their claims. The party must bear the expense, and the court weighs the opinion alongside other evidence.

The Offender Management Act 2007 explicitly provides that any statement made during a polygraph session, or any physiological reaction recorded, may not be used in criminal proceedings in which that person is the defendant [24]Verified Offender Management Act 2007 — Explanatory Notes
Confirms polygraph session statements may not be used in criminal proceedings against the tested person. This safeguard was designed to encourage honest disclosure during probation monitoring. For private tests, the results serve as a powerful tool for personal decision-making, relationship resolution, and building supporting evidence for legal cases. For more about the legal landscape, explore our UK polygraph information hub.