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Theft Lie Detector Test
This examination is conducted by accredited Lie Detector UK examiners, at any of our 124 offices.
When something has gone from a home or a business, the hard part is rarely establishing that a theft happened. It is narrowing down who was involved without accusing someone who was not.
A polygraph examines one specific question: whether a named person took a named item, or knows where it is. £495 for one person, £295 each for three or more, about two hours, written report in 24 to 48 hours.
It cannot identify a culprit from a group on its own — and a large part of its value is in the people it clears.
Who books this
- Households where something has gone from inside the home and the possibilities are few — often family, a lodger, or someone with a key.
- Businesses with stock, cash or data unaccounted for and a small number of people with access.
- People who have been accused of a theft they did not commit, and want it examined independently rather than argued about.
That third group is a substantial part of this work and the one least talked about. Being suspected is not the same as being guilty, and an examination is one of the few ways to have that tested rather than endlessly discussed.
What it can and cannot establish
It can examine
- Whether a person removed a named item or sum
- Whether they know where it is now
- Whether they were involved in a described event
- Whether they have given an accurate account
It cannot examine
- General honesty or character
- Who out of a group is responsible, in one sitting
- Anything the examinee does not know
- Vague suspicions with no specific act attached
Each person is examined separately, and the charts speak only to that person’s answers. A provider offering to identify a culprit from a group in a single session is describing something a polygraph does not do.
The questions decide whether it works
Up to three relevant questions, agreed in the pre-test consultation and seen by the examinee before the day.
| Not testable | Testable |
|---|---|
| “Have you ever stolen from us?” | “Did you take the £400 from the safe on 14 March?” |
| “Do you know anything about it?” | “Do you know where my mother’s ring is now?” |
| “Are you honest?” | “Have you removed stock from the warehouse without authorisation since January?” |
Precision protects the innocent as much as it catches the guilty. A broad question invites a broad reaction, and a reaction is not a lie.
In a workplace: consent is not a formality
An examination cannot proceed without the examinee’s written consent, given on the day, and it can be stopped at any point. Nobody can be required to take one as a condition of keeping their job, and a refusal is not a result and must not be recorded as one.
Take your own HR and legal advice before an examination forms part of any disciplinary process. We conduct the examination and report what the charts showed; what an employer does with that is not something we are qualified to advise on and will not pretend to be.
If your process cannot accommodate someone declining, the process is not ready to include an examination.
Where it tends to earn its money
In practice the greatest value is often in exclusion. A small team under suspicion is corrosive, and colleagues who volunteer and are found to show no deception get something an internal investigation rarely gives them: a documented, independent answer with their name on it.
Where several people are examined, the £295 per-examination rate applies from three upwards.
What happens on the day
- Arrival A first name at reception. Identification checked privately, consent signed. The office is an ordinary private room, not a clinic.
- Pre-test interview The longest part. Questions reviewed a final time, medical and medication history taken, normal responses established.
- The examination Three channels record continuously — breathing, pulse and relative blood pressure, and skin conductance. Only the examinee and the examiner are in the room, and it is video and sound recorded for analysis.
- Scoring Scored across all three channels against the examinee’s own baseline, result given before leaving, written report within 24 to 48 hours.
Nervousness is expected and appears on every chart. It is not mistaken for deception — the analysis compares responses against each other, not against a calm stranger. Someone anxious about being wrongly accused of theft is behaving normally.
The three possible results
| Result | Meaning |
|---|---|
| No deception indicated | No significant reaction to the relevant questions |
| Deception indicated | Significant, consistent reactions across channels |
| Inconclusive | The data does not support a call either way. A real outcome, not a failure to report one |
Where the report stands
A polygraph report is not admissible as proof in a UK criminal court and is not a substitute for a police investigation. Where a theft is a crime, report it.
What an examination provides is an independent, documented account of what a named person said — which is often what allows a family or a workplace to stop guessing, and sometimes what allows an insurer or an employer to close a matter that had stalled.
Accuracy and checking us
A validated technique conducted properly by an accredited examiner sits at 95 to 98 per cent. Polygraph services in the UK are unregulated, so verify before you pay anyone: our examiners are registered with the British Polygraph Society or the American Polygraph Association, and both keep public registers you can search.
Our guide to checking a provider is genuine sets out what else to ask.
Preparing
| Do this | Why |
|---|---|
| Sleep normally beforehand | Fatigue affects the recordings |
| Avoid caffeine and other stimulants | They alter the cardiovascular channel |
| Abstain from alcohol and recreational drugs for 24 hours | Observable impairment makes someone unsuitable for examination |
| Take prescribed medication as normal | Do not skip it. Disclose it at booking |
| Bring dates, amounts and names | The questions cannot be precise without them |
Source: APA Model Policy for Examinee Suitability, 9 September 2021.
What you receive
The result verbally at the end of the appointment, and the written report within 24 to 48 hours: the questions asked, the responses recorded, and the examiner’s stated opinion.
The report goes only to the person who commissioned it. If a third party needs to confirm a genuine examination took place, we can issue a pass code rather than releasing the report.
Booking
£495 all inclusive for one person, £695 for two examined separately, £295 each for three or more. A £150 deposit reserves the appointment and comes off the total, with the balance due 48 hours beforehand. No call-out charge to any office.
Call 020 8058 6848, Monday to Friday, 8am to 8pm, or find your nearest office.
Other formats
People also look at
Infidelity
Specific-issue testing on suspected physical or emotional involvement with someone else.
View format →False accusation
For people who need a documented, independent examination to answer an allegation.
View format →Theft
Workplace and domestic theft, tested individually rather than by group suspicion.
View format →Dispute resolution
Family and civil disputes where two accounts cannot both be true.
View format →Addiction
Abstinence monitoring, usually as part of an agreement between family members.
View format →Employee screening
Pre-employment and integrity testing for security-sensitive roles.
View format →Understanding lie detector services
What a real examination involves, and how to tell one from the things sold as lie detection.
View format →Common questions
The questions people actually ask us
How accurate is a lie detector test?
A validated technique, run properly by an accredited examiner, sits at 95–98%. Anyone quoting 100% is selling you something else.
Does being nervous affect the result?
No. Nervousness is expected and shows up on every chart. The analysis compares your responses against each other, not against a calm stranger.
What questions will be asked?
Up to three relevant questions, agreed with you in the pre-test consultation. Nothing is asked on the day that you have not already seen.
Can I refuse to take the test?
Yes, at any point, including once you are in the room. An examination in the UK cannot proceed without your written consent.
How long does the test take?
Around two hours in total. Most of that is the consultation and question review; the instrument phase is the shortest part.
Can I attend someone else’s test?
No — a third party in the room invalidates the examination. You are welcome to wait in reception and to see the written report if the examinee consents.
Do you offer home or on-site tests?
Tests are normally conducted at our private office in the UK, where the environment can be controlled. Alternative locations may be possible subject to pre-approval.
Do you test under 18s?
Only in limited circumstances, with the written consent of a parent or guardian, and at the examiner’s discretion. Please call to discuss before booking.
Do medications affect the results?
Tell your examiner what you take. Most prescriptions are fine; a few are not, and your examiner will say so before you pay the balance.
Can the test be cheated?
Countermeasures are what examiners are trained to spot. Attempting them typically produces an inconclusive result, not a pass.
How much does a lie detector test cost in the UK?
£495 all inclusive for one person and £695 for a couple, covering the consultation, the examination and a written report. A £150 deposit reserves the appointment.
