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Employee Pre-screening Lie Detector Test
Booked directly with Lie Detector UK, and conducted by an examiner on the BPS and APA registers.
Pre-employment screening asks a candidate to confirm on the record what a CV and an interview cannot verify. It is not a background check and does not replace one — it addresses what a candidate says about themselves, which is exactly the part references and databases cannot reach.
£495 per candidate, £295 each for three or more. Around two hours, written report in 24 to 48 hours.
Consent is required in writing and a refusal is not a result. If your recruitment process cannot accommodate a candidate declining, it is not ready to include an examination.
Where this is used
Roles where a single undisclosed fact would change the hiring decision:
- Access to cash, stock or high-value goods
- Access to client data or confidential systems
- Lone working, or work in customers’ homes
- Positions of trust involving vulnerable people
- Roles where a previous dismissal for dishonesty would be disqualifying
It is most useful where the concern is concrete. “Has this person ever been dismissed for dishonesty” can be examined. “Is this person trustworthy” cannot — there is no fact of the matter for an instrument to record, and no examiner should accept it.
What screening reaches that other checks do not
| Check | What it establishes | What it misses |
|---|---|---|
| DBS / criminal record | What is on record | Anything never charged or convicted |
| References | What a previous employer will put in writing | Anything a settlement agreement prevents them saying |
| Qualification checks | Whether a certificate exists | Nothing — this one works. Use it |
| Polygraph | What the candidate says about themselves, under examination | Everything the candidate does not know |
The honest framing is that these are complements, not substitutes. An examination is the narrow tool for the narrow gap.
What can and cannot be asked
Can be examined
- Whether the candidate has been dismissed for dishonesty
- Whether a stated qualification is genuine
- Whether a described event occurred
- Whether they have an undisclosed interest in a competitor
Must not be asked
- Anything touching a protected characteristic
- General character or “trustworthiness”
- Intentions, or future conduct
- Anything the candidate could not reasonably know
Up to three relevant questions, agreed in the pre-test consultation and seen by the candidate before the day. Nothing is asked that has not already been approved by everyone involved. Your examiner will tell you plainly if a question cannot be tested reliably — before you pay the balance, not after the appointment.
Consent, and the limits of an employer’s position
The candidate must consent in writing on the day, and can stop at any point, including once the instrument is attached.
- Nobody can be required to take an examination as a condition of employment.
- A refusal is not a result. It is the exercise of a right and must not be recorded as an adverse finding or treated as an admission.
- An examination taken under pressure produces nothing anyone can rely on.
Take your own HR and legal advice before a polygraph forms part of a hiring decision. We conduct the examination and report what the charts showed; how that is weighed is not ours to advise on.
What happens on the day
- Arrival The candidate gives a first name at reception. Identification checked privately, consent signed.
- Pre-test interview The longest part of the appointment. 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 candidate and the examiner are in the room, and it is video and sound recorded for analysis.
- Scoring Scored across all three channels against the candidate’s own baseline. Result given before they leave, written report within 24 to 48 hours.
A candidate being examined as part of a job application will be anxious. That is expected, appears on every chart, and is not mistaken for deception — the analysis compares their responses against each other, not against a calm stranger.
Who cannot be examined
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; and observable impairment through alcohol or drugs.
Source: APA Model Policy for Examinee Suitability, 9 September 2021.
Candidates should abstain from alcohol and recreational drugs for 24 hours beforehand, and take prescribed medication at its normal dose — disclosed at booking, not stopped.
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 — and should not be read as a negative finding |
That last row matters in recruitment more than anywhere else. An inconclusive result is not a soft “deception indicated”, and treating it as one is unfair to the candidate and unsafe for the employer.
Accuracy, and checking us first
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 engaging anyone — our examiners are registered with the British Polygraph Society or the American Polygraph Association, both of which keep public registers.
See our guide to checking a provider is genuine.
What you receive
The examiner gives the result before the candidate leaves, and the written report follows within 24 to 48 hours: the questions asked, the responses recorded, and the examiner’s stated opinion.
The report goes to the person who commissioned it and to nobody else without explicit written consent.
Booking
£495 all inclusive per candidate, covering the consultation, the examination and the report. Three or more examinations are £295 each. A £150 deposit reserves each appointment and comes off the total. No call-out charge to any of our offices.
Call 020 8058 6848, Monday to Friday, 8am to 8pm, to discuss whether your concern is one an examination can address — or find your nearest office.
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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.
