Frequently Asked Questions
Straight answers about polygraph testing in London: what it costs, how accurate it is, how to prepare and what happens on the day at our Paddington suite.
Before You Book
No, and the fact you are asking suggests you already know that. Nobody researches polygraph testing for fun. The question that brought you here has been costing you sleep, focus, or both, and a controlled test is the only clean way to retire it. Those who close this tab to think usually never return, and the question stays.
Your bank statement shows a short LPI reference, our parent company, and nothing else. There is no mention of polygraph or London Polygraph Services anywhere on the transaction, which matters when accounts are shared.
Consent is not optional in this work: a pressured examinee produces worthless charts, so we test volunteers only. The offer of a test, made calmly, is itself revealing. Acceptance says one thing, refusal another, and a discussion about why can settle more than the test itself sometimes would.
Contact us as early as you can and we will do our best to move your appointment to a day that works; life happens and we are used to it. And if you get as far as the car park and are not sure you can walk in, that is far more common than you would believe. Come in anyway and talk to the examiner. Nothing is recorded until you have agreed everything, and nobody will pressure you into anything.
That depends on the result, and we will not pretend otherwise. What we see most often is relief, whichever way it falls. A clean result gives couples solid ground to rebuild on, and a failed one replaces months of confusion with the facts needed to decide what happens next. Your written report is evidence rather than instinct, what you do with it is entirely yours, and we are always happy to talk it through afterwards.
Yes. Every office has a reception where a companion can wait while the test is conducted; 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.
Yes. Tests are conducted in English, and we can arrange a professional interpreter; contact us for a quote before you book. You are welcome to bring your own independent professional interpreter rather than a friend or family member, but please still contact us for a quote first, because an interpreted appointment takes longer.
Tests at Paddington run Monday to Friday, 9am to 5pm. If you require an evening or weekend test, our sister service Home Polygraph (homepolygraph.com) comes to your home seven days a week, evenings included. Booking enquiries are answered 24/7 whichever you choose.
Yes, as far as reception. Whoever comes with you waits there while the test is conducted; during the test itself only you and the examiner are in the room. Afterwards, the examiner can explain the result to anyone you have authorised in writing, your solicitor included, and the written report goes to the person named on the consent form.
On a weekday, often yes. The Heathrow Express runs from the airport to Paddington, and the office is a short walk from the station. The appointment takes around 90 minutes, so allow two hours on site plus the journey each way, and book a slot from the live availability on the booking page before you travel; if the day you need shows a slot, it is yours the moment you pay.
No. Paddington Central is outside the central London Congestion Charge zone. The ULEZ covers the whole of Greater London, so check your vehicle before you set off. The best parking is the APCOA Paddington Station Car Park, which is paid. Given the choice, we would suggest the train or tube: the office is a short walk from the station, using the exit next to the Circle and District line exit.
Understanding Polygraph Tests
A polygraph examination measures your physiological responses whilst you answer a series of carefully structured questions. The equipment monitors several indicators including heart rate, blood pressure, respiratory patterns, and skin conductivity. These measurements help identify stress responses that may indicate deception. The test doesn't actually "detect lies" directly, rather, it identifies physiological changes that occur when someone is being deceptive versus when they're telling the truth. Modern computerised polygraph systems have significantly improved accuracy, with studies suggesting reliability rates between 90-98% when administered by properly trained examiners.
The whole appointment takes around 90 minutes; allow two hours. It starts with the pre-test interview: your situation, the wording of every question, your rights and written consent. The examination itself follows, recorded throughout, and runs to three or more charts. Before you leave, the examiner explains the preliminary result, and the full written report with the charts is with you within 24 hours. None of it is rushed; a hurried pre-test interview makes a poor test.
You'll encounter three types of questions during your examination. Relevant questions address the specific issue under investigation (for example, "Did you take the money from the safe?"). Control questions help establish baseline responses and typically relate to similar but less specific concerns. Irrelevant questions are straightforward queries with obvious answers (like "Is your name John?") that help the examiner understand your normal physiological state. Crucially, every question is reviewed with you before the test begins, there are absolutely no surprise questions during a polygraph examination.
Absolutely. One of the fundamental principles of proper polygraph testing is complete transparency about the questions. During the pre-test interview, your examiner will review every question that will be asked during the actual test. We'll discuss the wording, ensure you understand each question clearly, and make any necessary adjustments. This isn't just good practice, it's essential for accurate results. You'll never be blindsided by unexpected questions during your examination.
Accuracy and Reliability
When administered by a qualified, experienced examiner using modern equipment, polygraph tests demonstrate accuracy rates between 90-98%. However, accuracy depends on several critical factors: the examiner's qualifications and experience, the quality of equipment used, the testing environment, and the examinee's physical and mental state. This is why it's essential to choose a properly accredited examiner who follows established protocols. Research by the American Polygraph Association, based on over 250 studies, consistently shows polygraph testing to be far more reliable than chance, though not infallible.
Several elements influence test accuracy. Your physical state matters, fatigue, illness, or the influence of drugs or alcohol can impact results. Mental state is equally important; extreme anxiety or certain medical conditions may affect physiological responses. The examiner's skill level is perhaps the most crucial factor, a properly trained professional knows how to account for nervousness and distinguish it from deception. Environmental factors also play a role; tests should be conducted in quiet, controlled settings free from distractions. This is why we insist on appropriate testing conditions and comprehensive pre-test screening.
No. This is perhaps the most common concern people have, and it's important to understand: nervousness will not cause you to fail a polygraph test. Experienced examiners are thoroughly trained to distinguish between general anxiety and the specific physiological responses associated with deception. Everyone feels nervous during a polygraph, it's completely normal and expected. The test specifically accounts for this by using control and irrelevant questions to establish your baseline responses when you're truthful. If you're being honest, nervousness won't cause a deceptive result.
Polygraph results are generally not admissible as primary evidence in UK courts. However, they serve valuable investigative purposes and are used in specific contexts such as sex offender monitoring and counter-terrorism supervision. Whilst courts don't typically accept polygraph results as proof, they can be instrumental in private investigations, employment disputes, and personal matters. The tests can also guide further investigation or help establish credibility. Some solicitors may request polygraph examinations to support their cases, even if the results themselves aren't presented in court.
Cost and Pricing
No. If your appointment is more than three days away you can secure it with a £199 deposit, and the balance is collected automatically from the same card two days before your test. Nothing to remember, nothing to pay on the day. The deposit is non-refundable, because it protects the appointment we hold exclusively for you, and if you would rather settle everything upfront you can pay in full, including in three instalments with Klarna.
The price on the page is the price. A single issue examination at Paddington is £493, a couples test £695, a theft investigation £548 and pre-employment screening £599, each booked and paid online with nothing added afterwards. Every test includes the pre-test interview, the recorded examination and the full written report with charts within 24 hours. Discounts apply when several people test on the same day, and interpreted appointments are quoted separately because they take longer.
Paying at booking is what confirms the appointment: the moment your payment goes through, the slot is held exclusively for you and the examiner's time is set aside. If your test is more than three days away you can secure it with a £199 deposit, and the balance is collected automatically from the same card two days before your test, so there is nothing to remember and nothing to pay on the day. The deposit is non-refundable because it protects the appointment we hold for you. If you would rather settle everything upfront you can pay in full, including in three instalments with Klarna. Whichever you choose, the price is the same and nothing is added afterwards.
No. The price on the page covers the pre-test interview, the recorded examination and the full written report with charts, and the preliminary result is explained before you leave. Home visits are a separate service, booked through Home Polygraph Services (https://homepolygraph.com) at its own fixed price. Two things are quoted separately because they take more of the examiner's time: an interpreted appointment, and expert witness work for legal proceedings. Both are agreed with you before you book, never added afterwards.
Yes, we offer reduced rates when multiple tests are conducted on the same day at the same location. This is particularly relevant in cases where both partners in a relationship require testing, or in workplace situations involving several employees. The discount reflects the efficiency of conducting consecutive examinations. Contact us directly to discuss your specific requirements and we'll provide a detailed quote for multiple examinations.
Preparation and Requirements
Proper preparation is straightforward. Get a good night's sleep (7-8 hours) before your test, as fatigue can affect your ability to focus and your physiological responses. Eat normally, don't skip meals, as low blood sugar can impact results. Continue taking any prescribed medications as directed by your doctor. Avoid alcohol for 24 hours before the test and avoid caffeine on the day of your examination, as stimulants can elevate your heart rate. Wear comfortable clothing that isn't too bulky (we'll need access to your torso and arms for the sensors). Most importantly, come prepared to be truthful and ask any questions you have during the pre-test interview.
There are several things to avoid before your examination. Don't consume alcohol or recreational drugs for at least 24 hours prior to testing, these substances can significantly affect your physiological responses and may lead to inconclusive results. Avoid energy drinks and excessive caffeine on the day of your test. Don't drastically change your normal routine or try special "techniques" you've read about online, these approaches don't work and often make results less reliable. Finally, don't discuss your upcoming test extensively with others who've taken polygraphs, as their experiences may create unnecessary anxiety or misconceptions about the process.
Many medical conditions don't prevent polygraph testing, but full disclosure is essential. During the booking process and pre-test interview, inform us of any medical conditions, particularly those affecting your heart, respiratory system, blood pressure, or nervous system. Certain conditions may require additional precautions or specific testing protocols. We also need to know about any medications you're taking. Pregnancy isn't typically a barrier to testing if the pregnancy is normal and uncomplicated. Your examiner will assess your suitability during the pre-test phase and may consult with medical professionals if necessary. Your safety and accurate results are our priorities.
Continue taking any prescribed medications as directed by your doctor, stopping prescribed medication can be dangerous and may affect results more than the medication itself. However, certain medications can influence physiological responses. Blood pressure medications, beta-blockers, anti-anxiety medications, stimulants, and antidepressants may all have effects we need to account for. This doesn't mean you can't take the test, but your examiner must know about them. During your pre-test interview, we'll discuss all medications (including over-the-counter drugs and supplements) to determine if any special considerations are needed or if results should be interpreted with this information in mind.
The minimum age for polygraph testing is typically 14 years, though this isn't a rigid rule. Suitability depends more on the individual's cognitive ability to understand the process, grasp the questions, and comprehend the concept of lying. A young person must be able to give informed consent and understand the implications of the test. For anyone under 18 years of age, we require written permission from a parent or legal guardian. We assess each young person individually to ensure they're suitable for testing. The pre-test interview is particularly important with younger examinees to ensure they fully understand what's happening.
The Testing Process
The day starts at reception at One Kingdom Street, where you say what your confirmation email told you to say. The first part of the appointment is the pre-test interview. The examiner goes through your situation, explains how the instrument works and shows you the sensors, and agrees the wording of every question with you, so there are no surprises once the recording starts. It is the time to raise anything that worries you. You then sign the consent form, confirming you are taking the test voluntarily, and the examination follows: three or more charts, recorded throughout, with only you and the examiner in the room during the test. The preliminary result is explained before you leave.
Photo ID: a driving licence or passport. Your confirmation email, which tells you what to say at reception. Comfortable clothing that is not too bulky, because the sensors go on your chest, arm and fingers. If the test concerns a business matter, any paperwork about the loss or the allegation can help the pre-test interview, though it is not essential. For a personal matter, bring nothing but yourself: the questions are agreed with you at the office, and any questions of your own can be asked there.
The preliminary result is explained to you at Paddington before you leave, in plain terms, with the examiner walking you through what the charts show. The full written report follows within 24 hours: the questions asked, the examiner's opinion, the analysis and the charts your result was scored from. Nothing is held back for a second appointment or a further fee.
Your comprehensive report includes several key elements. You'll receive detailed charts showing your physiological responses to each question, a professional analysis of these responses, and the examiner's expert opinion on your truthfulness regarding the specific issues tested. The report explains the testing methodology used, notes any factors that may have influenced results, and provides context for the findings. All reports undergo peer review by another qualified examiner to ensure accuracy and reliability. This documented evidence can be shared with relevant parties (with your permission) and serves as a professional record of the examination.
Privacy and Confidentiality
Absolute confidentiality is fundamental to our service. All information shared during your examination is kept strictly private and protected under our confidentiality agreements. Test results are only shared with parties you've explicitly authorised to receive them. We don't discuss your test with anyone else or share any information without your written consent. The only exception is if results indicate a serious safeguarding concern (such as ongoing abuse or danger to others), where we may have a legal obligation to report. This would be discussed with you. Your privacy is protected at every stage of the process.
You control who sees your results. As the person who commissioned the test, you decide who receives the report. If you're the examinee taking the test for someone else (employer, partner, etc.), results are shared with the party who commissioned the test, subject to your consent. For employment situations, results typically go to the employer or HR department. For private matters, you can choose to share or withhold results as you see fit. All parties accessing results must respect confidentiality. If tests are conducted as part of court proceedings or probation requirements, results may be shared with relevant legal or supervisory authorities.
We adhere to strict data protection regulations including UK GDPR requirements. All personal information, test data, and results are stored securely using encrypted systems with restricted access. Physical documents are kept in locked, secure locations. Only authorised personnel directly involved in your case have access to your information. Data is retained for a defined period as required by professional standards and legal obligations, after which it's securely destroyed. We never sell, share, or distribute your information to third parties. You have rights regarding your data, including the right to request copies of information held about you and, in certain circumstances, to request deletion.
Specific Use Cases
Polygraph testing can be an effective tool for addressing infidelity suspicions, though it should be approached thoughtfully. The test can provide definitive answers when verbal assurances aren't sufficient to rebuild trust. Many couples use polygraph testing as part of relationship counselling, finding that clear results either confirm suspicions (allowing them to make informed decisions) or dispel false accusations (helping rebuild trust). However, it's important to consider the impact on your relationship regardless of the outcome. We recommend discussing this option with a relationship counsellor. The test itself is confidential, sensitive to the emotional nature of such situations, and conducted with appropriate discretion.
We do provide employment-related polygraph services, though their use in the UK is more limited than in some other countries. Employment polygraph testing is typically used for positions involving sensitive information, security clearance requirements, or where trust and honesty are paramount (such as handling large sums of money). Pre-employment screening helps verify information provided on applications and assess suitability for positions of trust. We also conduct testing related to workplace theft or fraud investigations. It's important to note that employment polygraph testing in the UK must be conducted carefully with proper consent, and employees cannot be legally compelled to take such tests unless specified in certain regulated positions.
Polygraph examinations can be highly effective in workplace theft investigations, helping identify culpable individuals whilst clearing innocent employees. When theft occurs in an environment with multiple suspects, polygraph testing can narrow down the investigation quickly and accurately. This protects honest employees from ongoing suspicion whilst helping employers take appropriate action. Testing is entirely voluntary, employees cannot be forced to participate, but voluntary participation often indicates willingness to clear one's name. The process is handled sensitively and confidentially. Results can guide further investigation or disciplinary action, though they're typically one component of a broader investigation rather than the sole basis for employment decisions.
Whilst polygraph results aren't typically admissible as evidence in UK courts, they serve valuable purposes in legal contexts. Solicitors may commission polygraph examinations to inform their case strategy, assess witness credibility, or support settlement negotiations. Results can be powerful in demonstrating good faith or supporting your version of events, even if they aren't formally presented in court. In some civil cases, parties may agree to accept polygraph results as part of mediation or settlement discussions. Family law cases occasionally involve polygraph testing for custody or access matters. Discuss your specific legal situation with your solicitor to determine whether polygraph testing could be beneficial to your case.
Additional Common Questions
"Failing" a polygraph means the examination indicated deception regarding the relevant questions asked. If this occurs, the examiner will typically discuss the results with you, as sometimes there are factors that may have influenced the outcome (misunderstood questions, extreme anxiety about a particular topic, etc.). In some cases, a retest may be appropriate after addressing any issues identified. However, if results consistently indicate deception, this suggests the responses given weren't truthful. The consequences depend on why you took the test, employment decisions, relationship impacts, or legal implications vary by situation. Remember, the polygraph doesn't explain why deception was indicated, only that physiological responses suggested untruthfulness.
You always have the right to withdraw from testing at any point, but refusing specific questions during the actual test will compromise the results and may raise concerns. Remember, all questions are reviewed with you during the pre-test interview, this is when concerns about particular questions should be raised and addressed. By the time testing begins, you'll have already agreed to all questions. If you feel uncomfortable answering something, it's better to discuss this beforehand rather than refusing during the test itself. Simply not answering or answering inconsistently makes the test unreliable. Taking a polygraph is entirely voluntary, and you're free to decline testing altogether, but selective refusal undermines the process.
Inconclusive results occur in roughly 10-15% of examinations and mean the examiner couldn't confidently determine truthfulness or deception from the physiological responses measured. This can happen for various reasons: certain medical conditions, medications, extreme anxiety, inadequate sleep, poor health on the test day, or if the examinee moved significantly during the test. Inconclusive results don't suggest you're lying, they simply mean the data wasn't clear enough for a definitive determination. Depending on circumstances, a retest may be scheduled after addressing any factors that may have contributed to the inconclusive result. The retest would typically be conducted after ensuring optimal testing conditions.
We test in one place, our office at One Kingdom Street, Paddington Central, and it is deliberately easy to reach from anywhere in Greater London: the Elizabeth line, the Bakerloo, Circle and District lines, GWR services and the Heathrow Express all come into Paddington, and the office is a short walk from the station. From Croydon, Stratford, Harrow, Romford, Kingston and the rest of outer London, you come to us rather than the other way round, and the area pages on this site give the route from each. If you cannot travel, our sister service Home Polygraph (https://homepolygraph.com) tests at your home.
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