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Understanding Lie Detector Services
This examination is conducted by accredited Lie Detector UK examiners, at any of our 124 offices.
Polygraph services in the UK are unregulated. There is no licence to practise, no statutory register, and nothing stopping anyone buying an instrument and advertising tomorrow.
That single fact explains most of what follows. This page is about how to check a provider before you pay one — what carries weight, what does not, and what is being sold as lie detection that is not lie detection at all.
What a polygraph actually is
An instrument that records three physiological channels continuously throughout an examination:
It is a recorder, not a lie meter. No single reading means anything on its own — the examiner scores the pattern across all three channels against the examinee’s own baseline answers, afterwards, not live in the room.
A validated technique conducted properly by an accredited examiner sits at 95 to 98 per cent accuracy. Anyone quoting 100 per cent is selling you something else.
The regulatory position, stated plainly
No government body approves polygraph examiners. No qualification is legally required. Nobody is checking. The professional bodies are voluntary, which makes membership meaningful precisely because it is optional — but it is not enforcement, and nobody will stop a non-member operating.
The practical consequence is that the burden of checking falls on you, before you pay. The rest of this page is that checklist.
How to check a provider
- Look them up on a public register The British Polygraph Society and the American Polygraph Association both maintain registers anyone can search. Search the examiner’s name — not the company’s — and do not accept a logo on a website as evidence of membership.
- Get a named examiner before you pay You should be able to find out who will conduct the examination and what their training is. A provider who will not name the person is not one to book.
- Insist on a pre-test consultation The questions must be agreed with you before the day, and the examinee must see them beforehand. A provider who takes a deposit without discussing your questions is not running a validated format.
- Confirm you get a written report A verbal opinion on the day is not something you can rely on afterwards, show anyone, or check.
- Ask about court The honest answer is that polygraph evidence is not admissible as proof in a UK criminal court. Anyone who tells you their report proves innocence in court is wrong, and that single answer tells you a great deal about everything else they have said.
- Ask which format they use A validated format has a name — the UTAH, or the AF/MGQT. “Our own proprietary method” is not an answer.
What is being sold that is not a polygraph
Several products are marketed as lie detection and are not validated techniques. They do not record the physiological channels a polygraph records, and they carry no professional standing.
| Marketed as | What it actually is |
|---|---|
| Eye-tracking systems | Camera-based measurement of pupil and eye behaviour. A single channel, no instrument attached to the body, and no large-scale independent validation in real high-stakes cases |
| Voice-stress analysis | Software analysing recorded speech. Not a validated deception technique |
| Phone apps | Entertainment. No physiological recording of any kind |
| “Remote” or video examinations | Not possible. The instrument requires sensors physically attached to the body in a controlled room |
| Brain-based scanning | Research techniques not established for commercial deception testing |
If you are offered a “test” that involves no instrument attached to the body, no pre-test consultation and no written report, you are not being offered a polygraph examination — whatever it is called and whatever the price.
Consent, and what it protects
An examination in the UK cannot proceed without the examinee’s written consent, given on the day, and it can be stopped at any point, including once the instrument is attached.
Two things follow, and a provider who is vague about either is telling you something:
- An examination someone has been pressured into is worth nothing to anybody, whatever the charts show. Duress does not produce reliable data.
- A refusal is not a result. It should never be recorded as one, and a provider who encourages you to read a decline as an admission is not one to use. This matters most in employment, where nobody can be required to take a polygraph as a condition of keeping their job.
Who cannot be examined
Not everyone is suitable, and a responsible examiner will say so before taking payment rather than after. The American Polygraph Association’s model policy lists:
- Active psychosis or an unmanaged psychotic condition
- Functional maturity below the equivalent of twelve years old on psychometric testing
- Severe intellectual disability, with an IQ below 55
- Acute severe mental health conditions, or a need for continuous assistance
- Observable impairment through alcohol or drugs
Source: APA Model Policy for Examinee Suitability, 9 September 2021.
Separately, examinees are asked to abstain from alcohol and recreational drugs for 24 hours beforehand. Prescribed medication should be taken at its normal dose and disclosed at booking — not stopped for the appointment.
What an examination can and cannot do
It can address
- Specific, factual, bounded questions
- Whether a named person did a named thing
- Whether an account someone has given is accurate
- Up to three relevant questions per examination
It cannot address
- General character or trustworthiness
- Intentions or future behaviour
- Identifying a culprit from a group on its own
- Anything the examinee does not know
On that third point: each person is examined separately and the charts speak only to that person’s answers. A provider offering to “find out who did it” from a group in one sitting is describing something a polygraph does not do.
Where examinations are used
| Context | Typical use |
|---|---|
| Private and relationship | Infidelity, disputed accounts, allegations within a family |
| Clearing a name | Someone accused who has no formal route to be believed |
| Workplace | Internal allegations of theft or misconduct; pre-employment screening for specific roles |
| Post-conviction supervision | Used within the justice system rather than privately |
The legal position
Polygraph evidence is not admissible as proof of guilt or innocence in a UK criminal court. Use in civil proceedings is limited and at the court’s discretion.
What a report does provide is an independent, documented account of what a named person said under examination — which is what makes it useful in the situations above, none of which are courtrooms.
What an examination involves
- Pre-test consultation By phone, before the appointment. The questions are agreed here.
- Arrival A first name at reception. Identification checked, consent signed, and the examination video and sound recorded for analysis.
- Pre-test interview The longest part of the day. Questions reviewed a final time, medical and medication history taken, baseline established.
- The examination Three channels recording continuously, nobody else in the room. The shortest part of the appointment.
- Scoring and report Result given before leaving; written report within 24 to 48 hours, to the person who booked and nobody else without written consent.
Nervousness is expected and appears on every chart. It is not mistaken for deception, because the analysis compares an examinee’s responses against each other rather than against a calm stranger.
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 provider whose materials never mention inconclusive results is worth a second look. It is a real and unavoidable outcome, and omitting it is a commercial decision rather than a scientific one.
What it costs in the UK
A £150 deposit reserves the appointment and comes off the total, with the balance due 48 hours beforehand. There is no call-out charge for travel to any of our offices.
The cost of a genuine examination is mostly the examiner’s time — a consultation beforehand, around two hours on the day, and the scoring and report afterwards. A price well below the market rate is usually not buying that, and the most common way to reduce it is to skip the pre-test consultation, which is the part that makes the result mean anything.
Questions worth asking any provider
- Who is the examiner, and which professional body are they registered with?
- Which validated format will be used?
- Will I see the questions before the day?
- Do I get a written report, and how quickly?
- Who else receives the report?
- What happens if the result is inconclusive?
- Is the examination admissible in court? (The correct answer is no.)
A provider who answers all seven straightforwardly is probably fine. One who is vague about any of them has told you what you needed to know.
Talking to us
Call 020 8058 6848, Monday to Friday, 8am to 8pm. The consultation is free and carries no obligation, and if an examination is not the right answer for your situation we would rather say so on the phone than take a deposit.
You are welcome to check our examiners on the BPS or APA register before booking. See the examination formats we offer, what each costs, or where we can see you.
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.
