Frequently Asked Questions

All answers and professional opinions are provided by Our Client Support Team and Our Accredited Examiners. Please feel free to contact us if you would like further information.

Q: What is the price of a lie detector test?

A: Each lie detector test is unique but broadly the average fee is between £395 and £495 per person for a professional polygraph test conducted by an accredited examiner.

Beware cheaper substandard tests with dubious results from lone wolves who do not produce peer reviewed reports by professional, accredited polygraph examiners qualified in forensic psychology, criminology or other relevant skill set.

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Q: What is a Lie Detector Test?

A: “Also known as a polygraph examination. It is an intricate procedure involving state of the art equipment, experienced and trained examiners and a number of conditions to measure variables in a person to determine whether they are lying or telling the truth about a specific issue, incident or event.

Q: How does it work?

A: “The examiner measures countless variables including heart rate, perspiration, eye movement and more this is combined with the metrics and analysis provided by our state-of-the-art equipment and further techniques involved in high level intelligence”

Q: How Accurate is a test?

A: “We can provide an achievable 98% accuracy for our polygraph examination as we have a strict operating framework which relies on 4 main factors where conditions all need to be satisfied to the gold standard. An experienced and accredited examiner, up-to-date and highly effective modern polygraph testing equipment and interface, correct environment which is to be void of distraction or disturbance, pre-examination screening of the subject to make sure they abide to our conditions”

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London Polygraph Examiner Interview – Accuracy of Lie Detector Tests

Is it cheaper if I just have 1 question?

This is one of the most frequently asked questions we get. The price of a polygraph test is not dependent on the amount of questions you want the subject to be asked, and here’s why.

A lie detector test will become ineffective if too many questions, or too many different questions, are asked. When you see a tv show in which the examiner asks question after question after question, you should know that the show is for entertainment purposes – the results will not be accurate. Equally in asking one question, the same process, focus and procedure must be taken. If a company offers you a cheaper price for 1 question then please verify their credentials.

Let me explain this further; a polygraph test should only ever be used to gain the truth about one issue. Only one. Each question should be regarding the specific issue. This way, if the subject answers dishonestly on any of the questions he will fail the entire test because all the questions are related to that one, single issue.

Our professional polygraph examiners will only conduct examinations in accordance with testing procedures and protocols recognised by the American Polygraph Association. We will not conduct substandard examinations. A properly conducted polygraph examination will result in accuracy rates of 95 to 98 percent whereas an improperly conducted examination will result in accuracy rates that are no better than the flip of a coin. If you are told it is 100% accurate then there is something not quite right as any scientific test must consider variance.

Each session can take anywhere from 90 minutes to three hours to complete, but to answer the initial question ‘No, the price does not vary according to the number of questions asked’, because we will only ask the amount of questions needed to ensure an accurate result.

Why is a non refundable booking fee required?

The non-refundable booking fee confirms the customer’s intention to proceed with the booking and is used to cover costs we will have incurred, such as travel and venue expenses. The booking fee is paid at the moment of the booking and then subtracted from the total to be paid a minimum of 48 hours before the test.

The nature of our work requires our examiners to be flexible and involves travel time and costs. Therefore we require a £100 non-refundable booking fee payment when you book your appointment. The payment is non-refundable to ensure that the subject does in fact intend to take the test.

Without these measures in place, there is a temptation for a guilty party to book a test as proof that they have nothing to hide, and subsequently cancel the booking. Please be sure you or the test taker can, and intend to make the appointment when you book with us

We are a highly mobile polygraph service for client convenience, making ourselves available days, nights and weekends. This mobility requires us to be efficient in fee collection and scheduling. We would not be able to keep our fees so reasonable if after driving several hours, an examinee decided not to show up, leaving us with no work, no income and a long drive home. For these reasons, we do require £100 non-refundable booking fee WHEN you make your appointment.

Once an appointment is made, fees are non-refundable. You may certainly call for a free consultation at any time, we simply ask that you not schedule an appointment until you are certain you can make that appointment.

How to schedule a polygraph test in the UK?

Use our secure online booking system to request your preferred date, time and location for a lie detector test.

To proceed and confirm your booking we will require upfront payment of £100 deposit (non-refundable booking fee).

Once the payment is received you will receive a confirmation of your booking online

Our private lie detector testing services are available all over the UK through our network of controlled offices and residential outreach.

In a vast majority of cases we are able to arrange a test within a 1 – 2 days of the order being placed. For same or next day appointments we normally require a minimum of 4 hours to arrange the examination and payment in full is required when booking.

How many questions can be asked?

For accuracy the examiner will repeat a series of questions during the test a minimum of 3 times to ensure consistency. When seeking “yes” or “no” responses no more than 3 questions can be asked of the subject.  Changes or modifications to the precise wording of questions may possibly be made by the examiner to ensure they are defined and specific. Depending on the complexity of the case under investigation the examiner may wish to add a further question relative to the other 3.  This may be for expansion or confirmation of a result. The additional question will be at the sole discretion of the examiner if it is felt more evidence may be acquired. However, the norm is that only 3 questions are asked.

What questions can be proposed?

All questions proposed must elicit “yes” or “no” answers.

  • Connective words (conjunctions) such as “or”, “and” etc. cannot be used since they make questions obscure and multi-sided. This leads to inconclusive results.
  • Drawn out, lengthy questions are not recommended. The fewer words used to construct them, the better.
  • The more questions related to the same matter, the more authentic the results will be. The examiner will suggest a range of different ways to rephrase questions so that they encompass every facet.
  • All questions must evolve around facts that are known, not opinions.
  • Questions must be constructed on one matter at a time. Multiple issues cannot be covered because the answer to part of the question could be true and other parts false, leading to obscure and inaccurate results.
  • Our examiners are specially trained in wording questions correctly so you can rely on their expertise.


In matters of infidelity you can’t ask if the subject loves someone. The reason for this is because there are many different types and degrees of love. Any answer to this question would effectively be an opinion.

Asking the subject if they will ever do something again or if they will do something in the future is not permitted.  The polygraph is not a crystal ball and nor is the subject. For example, the subject may not at the time of the test intend to cheat on a partner but the next day could easily have a change of heart.

Raising things that may have been said or done during an argument is not a good idea. This especially applies if the person was under the influence of alcohol or drugs.  They invariably can’t remember exactly what was said or done in such circumstances. The accuracy of the test can be affected when a person simply cannot remember.

Questions related to sexual contact can be proposed. However, the examiner may rephrase them to avoid embarrassing or startling the subject.

If an issue is complex or acute, the subject will benefit from a written precis of all facts and detailed information that exists. The examiner can then pose statement based questions to verify the subject’s honesty or lack thereof.


When dealing with theft, up to 4 questions can be asked although ordinarily 3 are sufficient. Below are example questions that may be posed to someone suspected of stealing.

  • Do you know who stole ‘X’?
  • Did you steal ‘X’?
  • Do you know where the missing ‘X’ is?
  • Did you intend to steal ‘X’?
  • Did you benefit from stealing ‘X’?
  • Before the theft of ‘X’ occurred did you know it would happen on ‘X’ day?

False accusations

A person who has been falsely accused of something may take a lie detector to prove their innocence.   Statement verification is the most efficient method for this type of test.

Normally there is a mountain of background information leading up to false accusations. The polygraph examiner will benefit greatly from receiving a summary of events in order to formulate the appropriate statements that need to be verified.  Statement verification requires “yes” or “no” responses. Questions may be asked along the following lines:

  • Did you do ‘X’ as Mrs A stated?
  • When you denied being involved in ‘X’ were you lying?

Drug abuse:

If a subject is suspected of drug abuse, it is recommended that the individual has blood tests taken by a qualified medical professional so that the results are available.

  • All questions posed will elicit “yes” or “no” responses, for example:
  • Apart from the drugs mentioned, have you used any other illicit drugs in the past ‘X’ months?

Domestic abuse

Polygraph examinations conducted to establish domestic abuse are usually emotionally charged and need to be handled with sensitivity. Statement verification is the most appropriate way of establishing the truth. Questions must be unambiguous and precise:

  • Did you hit ‘X’ on the face with your hand?
  • Did you use your hands on ‘X’ without permission so as to cause harm?
  • Did you use swear words/expletives when rowing with you wife as she alleges?
Is there a minimum age limit for someone taking a polygraph test?

The short answer would be no. However, in order for the test to be accurate, the subject does need to possess a good level of language and to understand the concept of truthfulness. Some children under the age of 16 may not possess that comprehension, so this limit is set on that basis.

Why does it take so long?

Every single case we have is as important as the last, so the time spent on putting you at ease, making sure you know the process and explaining the importance of honesty is time well spent because it ensures that we get the most accurate results possible.

On the surface that does seem like a long time, but the actual polygraph test will usually take the least amount of time. The majority of the time will be taken up by us talking. We will discuss the issue at length, which means we can ask the most pertinent questions possible, which in turn gives the most accurate results. We need to make sure you are physically well enough for the test, and that you understand the difference between lying and telling the truth.

You will have the opportunity to tell your side of the story in full, and, once we have compiled a list of the questions to be asked you will be told what those questions are before the actual test begins. Once the polygraph examination is completed, we will then give you the results and discuss them before you leave. It is quite a lengthy procedure but it does go by quickly!

How long will I have to wait for the results?

A full detailed test report is provided via email to the client within 24 hours of the test having been conducted or 48 hours if sent via tracked mail, whichever is requested by the client to the examiner on the day of the examination. In certain circumstances, the examiner, will provide the results verbally on the day of the examination to the person who made the booking. However, on occasions the examiner may wish for the charts to be crossed examined by another examiner before providing the results in which case the results will not be given verbally

Do I need to come to a central office for a polygraph test?

We realise that one location will not be convenient for many people, so to that end we do travel to various locations across the country, as long as a suitable venue is available or your residential address satisfies the test criteria.

Why would anyone who is guilty agree to take a lie detector test?

If a person refuses the chance to clear their name using a polygraph, that alone does not suggest guilt. We have experienced many cases where the subject was just nervous about the experience and this is justifiable as it is not an experience which anyone is accustomed to on a regular basis. Our examiners provision for nervousness and are trained to counter defensive behaviour which can be often perceived as guilt for one matter but relate to another matter entirely.

What about Voice Stress Tests?

Voice stress testing is not as accurate or reliable as polygraph testing, so we do not use it in our examinations.

How can you justify 98% accuracy?

We can provide an achievable 98% accuracy for our polygraph examination as we have a strict operating framework which relies on 4 main factors where conditions all need to be satisfied to the gold standard.

  1. An experienced and accredited examiner from the top echelon of the industry
  2. Up-to-date and highly effective modern polygraph testing equipment and interface
  3. The correct environment which is to be void of distraction or disturbance
  4. Pre-examination screening of examinee to make sure they abide to our conditions

The American Polygraph Association (APA) will tell you that a properly conducted session, with specific questions will give a result of between 95% to 98% accuracy. As with any scientific experiment there is no guarantee of 100% as there are natural variances which need to be provisioned for and taken into consideration.

What happens if someone tries to beat the test?

Many people think they can beat the polygraph test, and in older versions of the test it was possible. However, with today’s technology, there are measures in place to detect any attempt to tamper with the test. Moreover, you would not only be up against the equipment, but you would also be trying to fool highly experienced and trained examiners, people who are well aware that some will try to beat the test.

I’m on prescription medication from my Doctor. Do I need to stop taking them?

Definitely not! Not taking your prescription drugs could be dangerous, and in fact, could interfere with the test. The vast majority of prescription drugs will not interfere with the accuracy of the test as we need you to be as ‘normal’ as you would be on any other day. In our pre-examination assessment we check for any medical conditions and advise accordingly.

Can nerves make me look guilty when I’m not?

This is a situation which has been exploited (unsuccessfully) by many people who think they can beat the polygraph. Nerves will NOT affect the outcome of the examination, and for good reason. If you are nervous at the beginning of the test, as most people are, you will remain nervous throughout the test. Your reactions to answering truthfully and deceitfully will still differ and will still look very different to each other, thus giving us a clear indicator of guilt or otherwise.

Does it hurt?

No. You may feel a slight discomfort or pressure from the blood pressure cuff on your arm, which is inflated for the duration of the test, but it is no more uncomfortable than if a nurse or Dr was taking your blood pressure. In fact, the cuff will be slightly less inflated than in a medical situation, so discomfort should be minimal, if at all.

I’d like to sit in on the test. Can I do that?

if you have brought someone to us for a lie detector, you being in the room, watching and listening, is almost guaranteed to distort the truth. Let’s face it, not many people will want to admit their guilt with their accuser sitting next to them, or even listening in! Most people find it easier to admit guilt to a stranger – that’s why counselling is so effective! So no, as much as we understand that you would want to sit in and hear what is being said, your presence would undermine the effectiveness of the test.

Q: How to find the best UK Lie Detector Test Service ?

With so many providers available to us, offering the same types of services online, it can be quite overwhelming deciding on which one to use. Finding the best UK Lie Detector test service is not straightforward.
0800 861 1058 (Free Helpline)