Frequently Asked Questions
Straight answers about polygraph testing at our Slough office: what it costs, how accurate it is, how to prepare, and what actually happens between arriving at Bath Road and leaving with a result.
Before You Book
People do not land on this page on a whim. If you have read this far, the question has usually been with you for months. Booking a test is not an accusation and it is not a verdict. It is a decision to find out. The regret we hear about most is the time spent deciding, not the test itself.
A short LPI reference and nothing else. The words polygraph, lie detector and Slough never appear on the transaction, so a shared statement gives nothing away.
Nobody can be tested against their will. Written consent is checked before anything starts, so a reluctant partner cannot simply be booked in. What the offer does is move things on. Agreeing says something. Refusing says something too. Either way you know more than you did, and it has cost you nothing.
Tests at the Slough office run Monday to Friday. Booking enquiries are answered around the clock by phone, WhatsApp and the enquiry form, so you can arrange a weekday slot at any hour. If you require an evening or weekend test, our home visit service runs seven days a week with the last examination starting at 8pm, booked online at https://homepolygraph.com.
Tell us as early as you can and we will do our best to move your appointment to another day. If you get as far as the car park on Bath Road and are not sure you can walk in, come in anyway and talk to the examiner. Nothing is recorded until every question has been agreed with you, and nobody will push you into anything.
That depends on what the result is, and we will not pretend otherwise. A truthful result gives a couple solid ground to rebuild on. A deceptive result replaces months of doubt with a fact to act on. Either way the written report is evidence rather than instinct. What you do with it is your decision, and you are welcome to call us to talk it through afterwards.
Understanding Polygraph Tests
A polygraph records what your body does while you answer a structured set of questions: breathing, cardiovascular activity and the electrical conductance of your skin. The instrument does not detect lies as such. It records the physiological changes that go with deception and the examiner scores those recordings against validated rules. Run properly, on a single issue, with modern computerised equipment, decision accuracy sits between 90 and 98 percent.
The whole appointment takes around 90 minutes, so allow two hours. The pre-test interview, where the issue is discussed and the questions agreed, is the longest part. The recording itself is short. Then the examiner scores the charts and gives you the preliminary result before you leave. None of it is rushed, because the time spent getting the questions right is what makes the result dependable.
Three kinds. Relevant questions go directly to the issue being tested, for example whether you took the money from the till. Comparison questions are about broader, less specific matters and give the examiner something to measure the relevant questions against. Neutral questions, such as whether today is a Tuesday, show what your recordings look like at rest. Every question is read to you and agreed before the sensors go on. There are no surprise questions in a polygraph examination.
Yes, always. Agreeing the questions is what the pre-test interview is for. Your examiner goes through each one with you, adjusts the wording until it means exactly one thing, and does not start recording until you are satisfied. A question you have not agreed cannot be asked. This is not a courtesy; a test on vague or unexpected questions produces results nobody can rely on.
Accuracy and Reliability
A single issue test run properly sits between 90 and 98 percent decision accuracy. What moves that figure is not mysterious: the examiner's training, the instrument, the room and the question technique. All four are worth asking about before you book with anyone. Research gathered by the American Polygraph Association, drawing on hundreds of studies, puts a properly conducted examination far above chance, though no test of any kind is infallible.
Your physical state matters: a night without sleep, illness, alcohol or drugs in your system can all muddy the recordings. Some medical conditions and medications need to be accounted for, which is why the examiner asks. The room matters, which is why we test in a private, solid-walled meeting room rather than wherever happens to be free. Most of all, the examiner matters. Telling nervousness apart from deception, and writing questions that cannot be misread, are skills that take training and practice.
No. Everyone is nervous when the sensors go on, and the scoring allows for it. The examiner compares your responses to different types of question, not your overall state. A truthful person who is shaking produces the same outcome as a truthful person who is calm. If you are telling the truth, being anxious will not turn that into a deceptive result.
Not as primary evidence, in general. UK courts do not normally admit polygraph results, though the test is used by the state in specific settings such as the supervision of certain offenders. Where it earns its place is outside the courtroom: private disputes, workplace investigations, family matters and the preparation of a case. Solicitors sometimes ask for an examination to inform their own view of a client's account, even when the report will never be put in front of a judge.
Cost and Pricing
No. If your appointment is more than three days away you can secure it with a £149 deposit, and the balance is taken automatically from the same card two days before your test. Nothing to remember and nothing to pay at the office. The deposit is non-refundable because it holds the appointment exclusively for you. If you would rather pay everything upfront you can, including in three instalments with Klarna.
A single issue test at our Slough office is from £449, booked and paid online. The price covers the pre-test interview, the examination in a private room at Bath Road and the written report with recorded charts inside 24 hours. Couples tests are from £695, theft investigations from £499 and pre-employment screening from £549. Nothing is added on the day.
Because that is what turns a slot on the calendar into a confirmed appointment. Pay in full, including in three instalments with Klarna, or, if your test is more than three days away, hold the date with a £149 deposit and let the balance be collected automatically two days before. Once you book, the room is reserved and the examiner begins preparing your case, and the appointment is held for nobody else. That is why the deposit is non-refundable, and why both sides can treat the date as settled.
Not for the standard service. The price you see at booking covers the interview, the examination and the written report with charts. Home visits are a separate service through Home Polygraph Services, booked online at https://homepolygraph.com with its own pricing. If you need something out of the ordinary, such as a recording of the session or an examiner's attendance elsewhere, ask before you book and we will tell you plainly what it costs.
The couples test covers both partners on the same issue, on the same day, for £695. For a workplace matter involving several members of staff, contact us before booking. We will quote for the group and arrange the day so that each person is seen separately and nobody is left waiting around.
Preparation and Requirements
Sleep as normally as you can the night before. Eat as you usually would; an empty stomach does you no favours. Take any prescribed medication exactly as you always do. Leave alcohol alone for 24 hours before the appointment and go easy on caffeine on the day. Wear something comfortable and not too bulky, because sensors go around your chest and on your arm and fingers. Then come in ready to answer honestly and to ask anything you want to ask in the pre-test interview.
Alcohol and recreational drugs for at least 24 hours beforehand, because they distort the recordings and tend to produce an inconclusive result rather than a helpful one. Energy drinks and heavy caffeine on the day. Any so-called countermeasures you have read about online: they do not work, examiners are trained to spot them, and trying them only undermines your own test. And do not spend the days before the test collecting other people's polygraph stories. They rarely help and often add worry you do not need.
Usually, yes. What matters is that we know in advance. Tell us at booking or in the pre-test interview about anything affecting your heart, breathing, blood pressure or nervous system, and about any medication you take. Some conditions call for a little extra care in how the test is run. An uncomplicated pregnancy is not normally a bar. The examiner makes the final call on the day, and if a test cannot be run safely and reliably it will not be run.
Keep taking whatever you have been prescribed; stopping medication to take a test is a bad idea on every count. Some drugs do affect the recordings, including beta blockers, blood pressure medication, sedatives and some antidepressants and stimulants. That rarely prevents a test, but the examiner has to know, so bring a list of everything you take, including anything bought over the counter. It is discussed in the pre-test interview and taken into account when the charts are scored.
As a guide, 14. The real test is whether the person can follow the process, understand the questions and grasp what it means to lie, and that is judged individually. Anyone under 18 needs the written consent of a parent or legal guardian as well as their own, and the pre-test interview is taken slowly to make sure a young person understands what is happening and agrees to it.
The Testing Process
It is the longest part of the appointment and the part that decides whether the result will be worth anything. The examiner explains how the instrument works and what the sensors measure, goes through the issue with you, and then builds the questions with you, word by word. You sign a consent form confirming that you are taking the test voluntarily. By the time the sensors go on there is nothing left to discover, and that is the point.
Photo ID, such as a passport or driving licence, which is checked before anything begins. If you take regular medication, a list of what and how much. If the test is about a workplace matter and the employer has paperwork about it, that can be useful in the interview but is not essential. Wear comfortable clothes without thick layers, because the sensors sit on your chest, upper arm and fingers.
You hear the preliminary result from the examiner before you leave Bath Road. The written report follows within 24 hours, with the recorded charts, the examiner's analysis and the questions asked, set out so that someone who has never seen a polygraph chart can follow it.
The questions exactly as they were asked, the charts recorded while you answered them, the scoring and the examiner's opinion on the issue tested. The report also sets out the technique used and notes anything that might bear on the result. It is written to be read by a third party, so you can show it to whoever you choose, and it is released only to the person named on the consent form.
Privacy and Confidentiality
Yes. What is said in the room stays between you and the examiner, and the result goes only to the person named on the consent form. We do not discuss your test with anyone else without your written say so. The single exception is a serious safeguarding concern, such as a risk of harm to a child, where there may be a legal duty to report; if that ever arose it would be explained to you. Appointments at Bath Road are staggered so that you never meet another client.
Whoever is named on the consent form, and nobody else. If you booked the test for yourself, that is you. If an employer commissioned it and you agreed to take it, the report goes to the employer, with your consent recorded before the test. How far it goes after that is for the named recipient to decide. We never release a report to a partner, relative or solicitor who rings up asking for it.
In line with UK GDPR. Your booking details, charts and report are held on encrypted systems that only the people working on your case can reach. Records are kept for as long as professional standards and the law require and then securely destroyed. We do not sell or pass on your information. You can ask to see what we hold about you and, in some circumstances, ask for it to be deleted.
Specific Use Cases
This is the issue most people book for. Where words have stopped working, the test gives an answer with evidence behind it, and it cuts both ways: it clears a partner who has been wrongly accused just as firmly as it confirms a suspicion. Go into it knowing that the relationship will be different afterwards whichever way the result falls, and that the examiner's job is the question in front of them, not the relationship. Many couples find the decision to book is the honest conversation they had been avoiding.
Yes, on a voluntary basis. Pre-employment screening suits roles where trust is the whole job: handling cash, holding keys, working with vulnerable people or sensitive data. The candidate must agree in writing and cannot be compelled, and a refusal should be treated with care rather than read as guilt. We also test in workplace investigations where money, stock or information has gone missing. Employers should take their own advice on how a result fits into their procedures.
It is one of the things it does best. When something has gone missing and several people had the opportunity, single issue testing lets each person clear themselves on the same agreed questions. The honest majority get out from under suspicion quickly, and the investigation narrows. Participation is voluntary and each person is tested alone. A result is a strong piece of evidence rather than a verdict, and it should sit alongside the rest of the investigation, not replace it.
Not usually as evidence in court, but that is not the only use a report has. Solicitors commission examinations to test a client's account before building a case on it, to support a negotiated settlement, or to show good faith. In family matters a report can help an allegation be looked at calmly. Ask your solicitor how a result would fit your situation before you book, and tell us if the report is going to be read by a lawyer so it is written with that in mind.
Additional Common Questions
A deceptive result means the charts showed the responses associated with deception on the relevant questions. The examiner tells you this before you leave and talks it through with you. Sometimes there is something to discuss, such as a question that meant more to you than it should have, and occasionally a retest on reworded questions is appropriate. More often the result stands. The report records that deception was indicated; it does not say why, and what happens next depends on who commissioned the test and what it was for.
You can stop the test at any point. What you cannot do is pick and choose once recording has started, because a test with gaps in it cannot be scored. The time to object to a question is the pre-test interview, where every question is agreed with you and nothing goes on the list without your say so. If something feels wrong, say so then and the examiner will reword it or take it out. Walking away is always your right; selectively refusing simply wastes the appointment.
Roughly one test in ten comes back inconclusive, which means the charts did not point clearly either way. It is not a fail, and it is not a pass. Common causes are poor sleep, illness, something taken before the test or a lot of movement in the chair. The examiner will tell you what they think caused it and, where it makes sense, arrange a retest once the cause has been dealt with.
Every office test takes place at Bath Road, and the office is placed to be reached easily: just off junction 6 of the M4, on the A4, with Maidenhead, Windsor, Uxbridge, Bracknell and High Wycombe all within about half an hour by road and Heathrow seven miles east. Where travelling is genuinely not possible, our sister service Home Polygraph Services tests at your home, booked online at https://homepolygraph.com.
Yes. The business centre at 268 Bath Road has a reception area where a companion can wait, and there is parking onsite, though spaces are limited. Nobody other than you and the examiner is in the room during the examination. Your confirmation email tells you what to say when you arrive.
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