Can you beat a lie detector? UK police increasingly using polygraph tests – here’s how people try to cheat
I’m officially a bad liar.
With a blood pressure cuff pumped tight around my arm, straps around my chest monitoring my breathing, and sensors on my fingers to pick up any traces of sweat, veteran polygraph test examiner Don Cargill says he can easily spot the signs I’ve told him a fib.
I’ve denied writing the number three on the piece of paper placed underneath my chair, in a simple exercise designed to show how my body reacts to lying. Even with nothing to lose, it’s an uncomfortable experience.
But while commonly associated with daytime television programmes like The Jeremy Kyle Show, the use of lie detectors is expanding within the criminal justice system.
And the answers people give could help determine whether or not they can see their children – or even land them back in jail.
Lie detector tests featured regularly on The Jeremy Kyle Show. Pic: ITV
In an office above a branch of Carpetright in west London, Mr Cargill carries out private polygraph tests. His clients have included foreign politicians accused of bribery, bodybuilders who want to prove they haven’t taken performance-enhancing drugs, and people accused of stealing from their family or being unfaithful to a spouse.
More and more are trying to cheat the polygraph using instructions found online, he says. “There’s a lot of techniques they do but we spot 90% of them or more.”
I’m asked to jump up and down and open my mouth before my test. Some people have pressed drawing pins into the bottom of their shoes, or even superglued tacks in their mouths, to create a pain response in their brain to distort the chart, Mr Cargill says.
He asks for identification to make sure a stand-in hasn’t been sent and carries out other simple tests to spot signs of sleep deprivation or illegal drug use.
A camera is trained on the subject’s eyes to make sure they don’t cross them or “zone out”, while a seat pad is in place to catch out anyone clenching their bottom.
All of these methods have been used to try to cheat the test, Mr Cargill says.
Sky’s Henry Vaughan takes a lie detector test
Can lie detectors be cheated?
It is possible to beat the polygraph, says Newcastle University Emeritus Professor Don Grubin, but it takes a lot of practice with the equipment and examiners are trained to spot the signs of anyone trying to trick the test.
Double child killer Colin Pitchfork – who was jailed for life after raping and strangling 15-year-olds Lynda Mann and Dawn Ashworth in Leicestershire in 1983 and 1986 – was recalled to prison in 2021 partly due to concerns he was using breathing techniques in a bid to beat the lie detector.
The Home Office says the polygraph records physiological changes in a person, quoting research from the American Polygraph Association which found deception is accurately detected in 80 to 90% of cases.
Since 2014, probation services have carried out more than 8,800 polygraph tests, while police have conducted more than 4,600, says Prof Grubin, who explains around 60 to 70% result in disclosures – where someone reveals relevant information.
His company, Behavioural Measures UK, has trained and supervised dozens of police and parole polygraph test examiners over the past decade, and like other experts in the field, he doesn’t like the term lie detectors.
The technology detects the “cognitive process” (or the brain working harder) when someone tells a lie, he explains.
The results of a polygraph test
The “real skill lies in the experience of the examiner”, says Mr Cargill, the chief executive of VAST Screening Technologies Ltd and the chairman of the British and European Polygraph Association.
“Nervous reactions are completely different from people telling lies,” he says. “Your heart rate physically increases because you’re triggering the autonomic nervous system, which triggers a fight, flight or freeze response. You want to run away.”
But critics, including University of Northumbria researchers Dr Marion Oswald, a professor of law, and associate professor Dr Kyriakos Kotsoglou, say much of the research is carried out by the industry itself and the accuracy can’t be tested in a real-life situation – because it is impossible to verify if someone has told a lie.
They say it is an intrusive “interrogation” technique used to illicit confessions, arguing the polygraph device itself is unnecessary and could be swapped for putting someone’s hand on a photocopying machine – a method apparently used by Detroit police and immortalised in cult American crime drama The Wire.
“If you can convince the subject that she or he is being monitored for lies and they believe it, then she or he will disclose more information,” says Dr Kotsoglou.
How are lie detectors used?
The results can’t be used as evidence in criminal courts but mandatory lie detector tests have been used as a licence condition for sex offenders since 2014, then rolled out to convicted terrorists in 2021 in the wake of the Fishmongers’ Hall attack.
They are also used by police and the security services to monitor the small number of terror suspects made subject to Terrorism Prevention and Investigation Measures (Tpims).
There is currently a three-year trial for their use on domestic abuse offenders, while the new Criminal Justice Bill proposes to extend this to convicted murderers who pose a risk of committing a relevant sexual offence on release.
The tests provide “invaluable information we would otherwise not have had about offenders’ behaviour which helps us to better protect the public”, the Ministry of Justice says.
The Metropolitan Police is looking into using lie detection technology to vet new recruits or root out corrupt officers following a string of damaging scandals, including the cases of Sarah Everard’s murderer Wayne Couzens and serial rapist David Carrick.
David Carrick and Wayne Couzens
But “this is still at an early research stage” and there are no imminent plans to use the technology in this way, the force says.
Others are turning to lie detectors to try to prove their innocence.
Kevin Duffy, 70, passed a polygraph test after he was convicted of sexually assaulting a child, but the results weren’t taken into account by the judge who jailed him for more than nine years.
His son Ryan Duffy, 44, says: “If there’s something that can be used when it’s one person’s word against another’s that can highlight some kind of evidence, why can’t it be used?
“If they are prepared to look at it after conviction for single case issues such as, ‘are you using public transport, hanging around schools’, and relying on data for probation services, then why can’t you use it beforehand?”
Kevin Duffy took a polygraph test to try to prove his innocence. Pic: Ryan Duffy
People can’t be sent back to prison for failing a test, but they can face further sanctions, such as stricter licence conditions, and they can be recalled for making disclosures that reveal they have breached licence conditions or indicate their risk has increased.
The information gathered can be shared with police to carry out further investigations, which could lead to charges, while those found trying to trick the polygraph can also be recalled to prison.
A government report last year revealed four convicted terrorists were sent back to jail as a result of lie detector tests – three were recalled after disclosing “risk-related information”, while the fourth didn’t comply with their polygraph licence condition.
Sensors pick up any traces of sweat during the polygraph test
An increasing number of police forces are using the polygraph, which is seen as a useful tool to monitor and assess the risk of people on the sex offenders’ register, allowing officers to concentrate stretched resources on those deemed the most dangerous.
At least 14 of the 43 territorial police forces in England and Wales are now using lie detectors, with 14 police officers and 11 staff qualified as polygraph examiners, according to figures obtained by Liberty Investigates.
The data shows 671 polygraph tests were carried out by the 13 forces who provided figures by calendar year, up from 458 in 2018, and a five-year high.
More forces are expected to start using the technology as the College of Policing makes available training through its “polygraph school”.
Polygraph tester Don Cargill reviews Henry’s results
Suspects facing lie detector tests
Testing is “only mandatory by way of conditional caution or a positive obligation of a Sexual Harm Prevention Order or Sexual Risk Order” imposed by the courts, says the National Police Chiefs’ Council, and “any police use of polygraph will form part of a wider and detailed risk management plan tailored to the individual concerned”.
But the University of Northumbria researchers say a non-statutory regime of testing is being carried out by some forces, including on suspects during criminal investigation.
People arrested on suspicion of committing online child sex offences, for example, could be asked to take a test as part of a risk assessment to determine whether they can have contact with children, including their own.
Figures obtained by Prof Oswald and Dr Kotsoglou, using freedom of information requests, show that at least 228 such polygraph interviews were carried out over six years.
Other responses indicated use in “voluntary” risk assessments of convicted sex offenders, including those who apply for removal from the sex offenders’ register, and ambitions to use polygraph testing for more general offences such as violence.
Prof Oswald says: “I think our concern is that should we really in this country be basing really serious criminal justice decisions in a legal system on a scientific technique that is highly contested, to put it mildly, and hasn’t, especially in the policing circumstance, been discussed by parliament?”
The College of Policing says: “The College is working closely with the NPCC to establish a Polygraph School so that policing in England and Wales has access to standardised learning and development in the use of the tool that is tailored to their operating environment.
“The College will develop operational advice so that forces using the tool have a consistent basis on which to do so whilst recognising the relevant legal provisions.”
A new test known as ‘polygraph in a box’ has been developed
What is the future for lie detectors?
The technology has existed in some form for around a century and now Mr Cargill has invented what he calls a “completely revolutionary” Validated Automated Screening Technology (VAST) system – or “polygraph in a box”.
Programmed to find out anything from whether someone has massaged the qualifications on their CV to if they’re a member of an international terrorist organisation, he says the device is as accurate as any polygraph examiner and is already being used by police in the UK.
But the testing time is reduced to around 20 minutes from three hours and can be used with just 15 minutes training.
After filling out a questionnaire, the subject – attached to the device, wearing headphones and sensors on their fingers and palm – is instructed to silently answer “no” to the questions by a person in a recorded video on the screen. A human then grills them about any responses that indicate deception.
“I call it a truth verifier rather than a lie detector because what it’s doing is testing integrity,” explains Mr Cargill.
The technology, he says, would be ideal for use in police vetting and he wants to see it rolled out to areas such as Border Force, where officers could verify someone’s age or country of origin.
UK
Mandelson appointment was ‘worth the risk’ despite ‘strong relationship’ with Epstein, says minister
Appointing Lord Mandelson as the UK’s ambassador to the US was “worth the risk”, a minister has told Sky News.
Peter Kyle said the government put the Labour peer forward for the Washington role, despite knowing he had a “strong relationship” with convicted sex offender Jeffrey Epstein.
It is this relationship that led to Peter Mandelson being fired on Thursday by the prime minister.
Lord Mandelson and Jeffrey Epstein. File pic
But explaining the decision to appoint Lord Mandelson, Business Secretary Mr Kyle said: “The risk of appointing [him] knowing what was already public was worth the risk.
“Now, of course, we’ve seen the emails which were not published at the time, were not public and not even known about. And that has changed this situation.”
Speaking to Sunday Morning with Trevor Phillips, he rejected the suggestion that Lord Mandelson was appointed to Washington before security checks were completed.
He explained there was a two-stage vetting process for Lord Mandelson before he took on the ambassador role.
The first was done by the Cabinet Office, while the second was a “political process where there were political conversations done in Number 10 about all the other aspects of an appointment”, he said.
This is an apparent reference to Sir Keir Starmer asking follow-up questions based on the information provided by the vetting.
Please use Chrome browser for a more accessible video player
‘We knew it was a strong relationship’
These are believed to have included why Lord Mandelson continued contact with Epstein after he was convicted and why he was reported to have stayed in one of the paedophile financier’s homes while he was in prison.
Mr Kyle said: “Both of these things turned up information that was already public, and a decision was made based on Peter’s singular talents in this area, that the risk of appointing knowing what was already public was worth the risk.”
Mr Kyle also pointed to some of the government’s achievements under Lord Mandelson, such as the UK becoming the first country to sign a trade deal with the US, and President Donald Trump’s state visit next week.
Mr Kyle also admitted that the government knew that Lord Mandelson and Epstein had “a strong relationship”.
“We knew that there were risks involved,” he concluded.
PM had only ‘extracts of emails’ ahead of defence of Mandelson at PMQs – as Tories accuse him of ‘lying’
Speaking to Sky News, Kyle also sought to clarify the timeline of what Sir Keir Starmer knew about Lord Mandelson’s relationship with Epstein, and when he found this out.
It follows Conservative Party leader Kemi Badenoch accusing the prime minister of “lying to the whole country” about his knowledge of the then US ambassador’s relationship with the paedophile.
Allegations about Lord Mandelson began to emerge in the newspapers on Tuesday, while more serious allegations – that the Labour peer had suggested Epstein’s first conviction for sexual offences was wrongful and should be challenged – were sent to the Foreign Office on the same day by Bloomberg, which was seeking a response from the government.
But the following day, Sir Keir went into the House of Commons and publicly backed Britain’s man in Washington, giving him his full confidence. Only the next morning – on Thursday – did the PM then sack Lord Mandelson, a decision Downing Street has insisted was made based on “new information”.
Read more:
Witch-hunt vibe in Labour on who approved appointment
Senior Labour MP demands answers over Mandelson vetting
Please use Chrome browser for a more accessible video player
Vetting ‘is very thorough’
Speaking to Sunday Morning with Trevor Phillips, Mr Kyle said: “Number 10 had what was publicly available on Tuesday, which was extracts of emails which were not in context, and they weren’t the full email.
“Immediately upon having being alerted to extracts of emails, the Foreign Office contacted Peter Mandelson and asked for his account of the emails and asked for them to be put into context and for his response. That response did not come before PMQs [on Wednesday].
“Then after PMQs, the full emails were released by Bloomberg in the evening.
“By the first thing the next morning when the prime minister had time to read the emails in full, having had them in full and reading them almost immediately of having them – Peter was withdrawn as ambassador.”
Please use Chrome browser for a more accessible video player
Government deeming Mandelson to be ‘worth the risk’ is unlikely to calm Labour MPs
The Conservatives have claimed Sir Keir is lying about what he knew, with Laura Trott telling Sky News there are “grave questions about the prime minister’s judgement”.
The shadow education secretary called for “transparency”, and told Sunday Morning with Trevor Phillips: “We need to understand what was known and when.”
Laura Trott says there are ‘grave questions about the prime minister’s judgement’
They believe that Sir Keir was in possession of the full emails on Tuesday, because the Foreign Office passed these to Number 10. This is despite the PM backing Mandelson the following day.
Ms Trott explained: “We are calling for transparency because, if what we have outlined is correct, then the prime minister did lie and that is an extremely, extremely serious thing to have happened.”
She added: “This was a prime minister who stood on the steps of Downing Street and said that he was going to restore political integrity and look where we are now. We’ve had two senior resignations in the space of the number of weeks.
“The prime minister’s authority is completely shot.”
But Ms Trott refused to be drawn on whether she thinks Sir Keir should resign, only stating that he is “a rudderless, a weak prime minister whose authority is shot at a time we can least afford it as a country”.
UK
‘Minority’ who attacked police at ‘Unite the Kingdom’ rally ‘will pay a price’, minister says as up to 150,000 people march in London
People who attacked and injured police officers at a march organised by far-right activist Tommy Robinson “should and will pay a price” for their violence, the business secretary has said.
Peter Kyle condemned the bad behaviour at the “Unite the Kingdom” event in London on Saturday, which saw up to 150,000 take part in the rally.
Appearing on Sunday Morning With Trevor Phillips, Mr Kyle said the number of people who turned up showed that free speech is “alive and well” in the UK.
He said: “It doesn’t disturb me, because it’s actually proof that we live in a country where free speech, free association, is alive and well.
“The bit that disturbs me is that when a minority go to an extreme and end up perpetrating violence against the police – that is unacceptable and those people should and will pay a price for it.”
Home Secretary Shabana Mahmood vowed that anyone found to have taken part in criminal activity would “face the full force of the law” – as police said at least 25 people were arrested and 26 officers were injured – including four who were seriously hurt.
Prime Minister Sir Keir Starmer posted on X: “People have a right to peaceful protest. It is core to our country’s values.
“But we will not stand for assaults on police officers doing their job or for people feeling intimidated on our streets because of their background or the colour of their skin.
“Britain is a nation proudly built on tolerance, diversity and respect. Our flag represents our diverse country and we will never surrender it to those that use it as a symbol of violence, fear and division.”
Protesters forming the rally gathered in the centre of the capital, holding Union and St George’s flags.
Mr Kyle said: “The flag was waved quite a lot and I do want to make the point that the flag belongs to all of us.
“That flag means a lot of different things to a lot of people, but it is about essential British and English values and principles.
“Those English values and principles include free speech, freedom of association and the like, and all of those things are demonstrated just by the fact that that protest went along and that demonstration went along completely freely, it shows that those values are actually alive and well.”
Activists fly flags and carry wooden crosses during the ‘Unite the Kingdom’ march in London. Pic: Reuters
Protesters heard a series of speeches, including from Robinson, who called it the “biggest freedom of speech” in British history.
Police estimated that between 110,000 to 150,000 attended the event.
An anti-racism counter-protest, attended by about 5,000 campaigners, also took place, with the two groups clashing on Whitehall and Trafalgar Square, separated by lines of police.
The Metropolitan Police‘s Assistant Commissioner Matt Twist said officers faced “significant aggression” from “Unite the Kingdom” attendees.
“The violence they faced was wholly unacceptable,” he said.
“Twenty-six officers were injured, including four seriously – among them broken teeth, a possible broken nose, a concussion, a prolapsed disc and a head injury.”
People have been arrested for a range of offences, including affray, violent disorder, assaults, and criminal damage.
Please use Chrome browser for a more accessible video player
Protesters clash with police
Police said the Robinson crowd was too big to fit into Whitehall and a confrontation happened when police tried to stop them from encircling counter-protesters and accessing the area from different routes.
A Met spokesman said: “When officers moved in to stop them, they faced unacceptable violence. They were assaulted with kicks and punches. Bottles, flares and other projectiles were thrown.”
Officers continued to face aggression in multiple locations, in particular at the north of Whitehall as they worked to create a safe exit route for those who had been taking part in the Stand Up To Racism protest.
Robinson supporters hurled projectiles at counter-demonstrators as both groups faced off on Whitehall, police said.
A row of police horses stood opposite a crowd waving Union flags, and at one point, a glass bottle seemed to strike one of the horses, causing both the animal and its rider to stumble backward.
‘Unite the Kingdom’ protesters in Trafalgar Square. Pic: Reuters
Protesters in Whitehall. Pic: Reuters
Activists take part in the March Against Fascism, organised by Stand Up To Racism. Pic: PA
Musk makes surprise appearance
Robinson live-streamed the rally on X, with its audience peaking at 2.9 million viewers on Saturday afternoon.
Making a surprise appearance via video link, tech billionaire Elon Musk called for a “change of government” in the UK.
“You can’t – we don’t have another four years, or whenever the next election is, it’s too long,” Musk told the crowd. “Something’s got to be done. There’s got to be a dissolution of parliament and a new vote held.”
TV presenter Katie Hopkins also spoke after earlier appearing alongside Robinson, Lawrence Fox and Ant Middleton at the front of the march.
Katie Hopkins and Tommy Robinson at the rally. Pic: PA
‘Revolution has started – you can’t stop it’
With a voice which sounded hoarse from shouting, Robinson told crowds during his speech that “millions” had showed up for the rally.
“The dam has well and truly burst,” he said. “The cat is out of the bag and there is no putting it back in. The silent majority will be silent no longer.”
Addressing the prime minister and the Labour government, Robinson said: “The revolution has started – and you can’t stop it.”
Referring to a Court of Appeal decision to overturn an injunction blocking asylum seekers being housed at The Bell Hotel in Epping, Essex, Robinson claimed UK courts found the rights of undocumented migrants supersede those of the “local community”.
He said: “They told the world that Somalians, Afghanis, Pakistanis, all of them, their rights supersede yours – the British public, the people that built this nation.”
The Home Office will return migrants to France for the first time next week under the terms of a new deal, Sky News understands.
The agreement, which was signed in July, saw migrants first detained on 6 August, and they will now be flown back to the continent.
The ‘one in, one out’ deal means the UK can send people back to France if they have entered the country illegally. In exchange, the UK will allow asylum seekers to enter through a safe and legal route – as long as they have not previously tried to enter illegally.
It is a pilot scheme for now, which will be in place until June 2026.
Read more: How UK-France migrant returns deal works
Please use Chrome browser for a more accessible video player
UK-France migrant returns deal explained
The scheme comes amid growing public anger over immigration, with the issue recently becoming voters’ top concern for the first time since Brexit.
On Saturday, up to 150,000 people marched in London, gathering around Westminster in a protest dubbed ‘Unite the Kingdom’, and organised by far-right activist Tommy Robinson. There were a number of clashes with police, leading to 25 arrests and 26 police officers being injured.
Laura Trott, the shadow education secretary, said the “horrendous incidents” of violence were “completely abhorrent”, and said she was glad to hear those involved will feel the force of the law.
But speaking on Sunday Morning with Trevor Phillips, she warned that the protest shows that people feel “let down” by the government on immigration.
Ms Trott told Sky News: “There is clearly an issue in this country at the moment about immigration and migration. People clearly feel let down by a government that came in and said they were going to ‘smash the gangs’. And what we’ve seen is an increase in migration.
“We are not seeing the action from this government, which is distracted by scandal after scandal.”
Please use Chrome browser for a more accessible video player
Public feel ‘let down’ on immigration
She also accused Sir Keir Starmer of being a “rudderless prime minister”.
Business Secretary Peter Kyle said that violence against police is “unacceptable” but said it is “proof that we live in a country where free speech, free association is alive and well”.
On immigration, he insisted that the government is “straining at the bit to get a grip on the migration crisis”, which Mr Kyle said Labour “inherited from the Conservatives”.
Please use Chrome browser for a more accessible video player
‘Free speech is alive and well’
“We’ve been doing everything we can,” he said.
“The lesson is that by cooperating with our partners, France, rather than rowing with them, we are able to deliver.
“So I hope the flights will start as quickly as possible.”
But he said he was unaware of the exact date.
Mr Kyle added that ministers were “also angry about what we’ve inherited” and that they were doing “everything possible to get a grip on it”.
The number of migrants arriving in the UK after crossing the English Channel has topped 30,000 for the year so far.
It is the earliest point in a calendar year at which the 30,000 mark has been passed since data on the crossings was first reported in 2018.
-
Sports3 years ago‘Storybook stuff’: Inside the night Bryce Harper sent the Phillies to the World Series
-
Sports1 year agoStory injured on diving stop, exits Red Sox game
-
Sports2 years agoGame 1 of WS least-watched in recorded history
-
Sports2 years agoMLB Rank 2023: Ranking baseball’s top 100 players
-
Sports2 years agoButton battles heat exhaustion in NASCAR debut
-
Sports4 years ago
Team Europe easily wins 4th straight Laver Cup
-
Environment2 years agoJapan and South Korea have a lot at stake in a free and open South China Sea
-
Environment11 months agoHere are the best electric bikes you can buy at every price level in October 2024