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.
Image: 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.
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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.
Image: 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.
Image: 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.
Image: 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?”
Image: 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.
Image: 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”.
Image: 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.
History of the lie detector
The polygraph machine was invented in 1921 by police officer John Larson in Berkley, California, and has been used by US law enforcement agencies ever since and spread across the world.
His work was picked up by Leonard Keeler, who is widely credited as the inventor of the modern lie detector.
In the 1990s, the polygraph entered the computer age as statisticians at Johns Hopkins University developed an algorithm to analyse the data collected.
Jack Ruby, who shot dead Lee Harvey Oswald two days after he assassinated John F Kennedy requested and was granted a polygraph test to try to prove he was not involved in a conspiracy with Oswald – but then FBI-director J Edgar Hoover said the technique was not “sufficiently precise” to judge truth or deception “without qualification”.
Notable failures include CIA agent Aldrich Ames, who passed two polygraph tests while spying for the Soviet Union.
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.”
Image: 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.
An MP has told Sky News she was attacked online by the Tate brothers after she participated in a debate in the House of Commons about violence against women.
The controversial duo, Andrew and Tristan Tate, are facing charges of rape and human trafficking in the UK – all of which they deny.
But they are still very active online, and according to Sorcha Eastwood, the MP for Lagan Valley, are targeting her.
In a document seen by Sky News, Tristan Tate has highlighted one of the MP’s tweets and writes in private correspondence: “MP, nice target, can we sue her?”
Sorcha Eastwood says at first she thought the replies were from parody accounts and not the Tate brothers.
Her original tweet was about Elon Musk, not the Tate brothers. The MP said Musk’s tweets should be looked at through a counter-extremism lens.
“I was really concerned, I was concerned because to me that is a direct attack for want of a better phrase on me serving my constituents.
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“I couldn’t believe that they decided to pick this random Northern Irish MP. The fact that it wasn’t even about them. This is something I didn’t go looking for.
“I think from my perspective, it’s a very, very sinister attempt to shut down important voices in public life, political discourse.”
It was only when she started noticing an uptick in abuse from other accounts she realised she had encountered some of the brothers’ followers.
“I had rape threats. I had death threats. I had people saying I should be hung from a lamppost. I had people saying I should be chopped into liver. I also had people then who were like we’ll waste 15 minutes raping Sorcha Eastwood.”
Image: A representative for the Tate brothers told Sky News that there was no targeted campaign against Sorcha Eastwood
A representative for the Tate brothers told Sky News that there was no targeted campaign against her.
They said: “Ms Eastwood has a distorted view regarding social media if she believes one is required to ‘invite or ask’ people to interact.
“Tristan Tate is entitled to his view in relation to her tweet regarding Elon Musk.”
The self-styled “misogynist influencer” Andrew Tate and his brother Tristan have both been charged with human trafficking, face allegations of trafficking minors, sexual intercourse with a minor and money laundering in Romania.
There is also a European arrest warrant for them as they are facing separate, unrelated charges of rape and human trafficking in the UK. They deny all charges.
Ms Eastwood now worries for others who don’t have a platform like her and who may not feel like they can speak out.
“If this is what has happened to me I have absolutely no doubt that this has happened to others where they have been attempted to be silenced.”
Keir Starmer has previously commented on the Tate brothers’ case in the Commons saying it is “a live issue”, but adding that “the principle is absolutely clear” in relation to whether the brothers should face justice.
Sorcha Eastwood says she wants to see the government do much more to protect against abuse online.
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Tate brothers deny wrongdoing
“I think ultimately the government has taken the wrong course on this. They need to step up.
“This should be an issue of national security as far as the radicalisation of young people online. It should be an issue in terms of the levels of misinformation, disinformation and the lack of trust that is had in our politics right across the UK and Europe.
“I want the government to help me, help every other person to crack down on this and get serious about it. And the only way they’ll be able to do that, is by hitting these tech companies in the only language which they understand, which is money and via robust legislation.”
A government spokesperson said: “Violence against women and girls is a scourge on our society which is why we have set out an unprecedented mission to halve these crimes within a decade.
“Tackling illegal abuse both online and offline is central to supporting victims and preventing harm in our communities and we will not hesitate to strengthen laws to deliver this mission.
“Last month, parts of the Online Safety Act came into force meaning companies must take action to protect users from illegal material including extreme sexual violence.
“Further protections from this summer will require platforms to protect children from harmful, misogynistic, and violent content.”
In parts of Birmingham, the stench is overwhelming – enough to make you heave.
At a block of flats in Highgate, in Birmingham city centre, we find a mountain of bin liners full of rubbish spewing out of the cavernous bin store, which is normally locked.
Mickel comes out to speak to us, while all around bin liners lie open, with the contents for all to see, including used nappies and rotting food.
Image: Mickel says they’ve had ‘foxes and rats, literally the size of cats’
Image: Outside Mickel’s flat in Highgate, bin liners lie open, spewing out rubbish
We both find it hard to keep talking amid the awful smell.
“We’ve had foxes and rats, literally the size of cats, flies, it’s just nasty, something needs to be done,” he says.
Image: Chris says the situation is ‘overwhelming’ as she’s ‘terrified of rats’
Around the corner, I meet Chris, in her dressing gown, popping the bins into her bin store beneath her flat before work.
She unlocks it, and although it isn’t bursting out on to the street yet, it is getting full.
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She says the situation is “overwhelming” as she’s “terrified of rats”. But, even so, she has sympathy for the striking bin workers.
“It’s not an easy job; they must have a heart of gold to do that job,” she says.
“Pay them whatever they need, they deserve it.”
Image: Striking bin workers at Lifford Lane tip, south of the city centre
Image: There’s an awful smell coming from a mountain of bin liners outside Mickel’s flat in Highgate
At Lifford Lane tip, south of the city centre, Brigette has pulled up alongside picketing workers. The back seat of her car is full of rubbish.
She apologises for the terrible waft, mixed with air freshener.
“It’s very pungent, isn’t it? Not nice,” she admits.
“It’s unfortunate, I have some sympathies for all the parties, but, equally, we have a duty of care to stay clean and tidy.”
She says she has her rubbish and that of her elderly aunt and plans to make weekly trips to the tip until a resolution in this pay dispute between the council and the Unite union is found.
The US is “our closest ally” but “nothing is off the table” in response to Donald Trump’s 10% tariffs on imports from the UK, the business secretary has said.
In a statement following the US president’s nearly hour-long address to the world, Business and Trade Secretary Jonathan Reynolds said: “We will always act in the best interests of UK businesses and consumers.
“That’s why, throughout the last few weeks, the government has been fully focused on negotiating an economic deal with the United States that strengthens our existing fair and balanced trading relationship.”
Mr Reynolds reiterated the statements from the prime minister and his cabinet over the past few days, saying the US is “our closest ally”, and the government’s approach is to “remain calm and committed to doing this deal, which we hope will mitigate the impact of what has been announced today”.
Image: Business Secretary Jonathan Reynolds says “nothing is off the table” following the tariffs announcement. Pic: PA
But he continued: “We have a range of tools at our disposal, and we will not hesitate to act. We will continue to engage with UK businesses, including on their assessment of the impact of any further steps we take.
“Nobody wants a trade war, and our intention remains to secure a deal. But nothing is off the table, and the government will do everything necessary to defend the UK’s national interest.”
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‘Get back round the negotiating table’, say Tories
The Conservative Party’s shadow business and trade secretary described the US president’s announcement as “disappointing news which will worry working families across the country”.
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Sky’s Ed Conway examines how economies across the world are impacted by tariffs
Andrew Griffith hit out at the government for having “failed to negotiate with President Trump’s team for too many months after the election, failed to keep our experienced top trade negotiator, and failed to get a deal to avoid the imposition of these tariffs by our closest trading partner”.
“The chancellor’s emergency budget of just a week ago with its inadequate headroom is now at risk, casting uncertainty about more taxes or spending cuts,” he continued. “Sadly, it is British businesses and workers who will pay the price for Labour’s failure.”
He called on ministers to “swallow their pride” and “get back round the negotiating table to agree a fair deal to protect jobs and consumers in both the UK and the US alike”.
Relief in Westminster – but concessions to Trump to come
It has been quite a rollercoaster for the government, where they went from the hope that they could avoid tariffs, that they could get that economic deal, to the realisation that was not going to happen, and then the anticipation of how hard would the UK be hit.
In Westminster tonight, there is actual relief because the UK is going to have a 10% baseline tariff – but that is the least onerous of all the tariffs we saw President Trump announce.
He held up a chart of the worst offenders, and the UK was well at the bottom of that list.
No 10 sources were telling me as President Trump was in the Rose Garden that while no tariffs are good, and it’s not what they want, the fact the UK has tariffs that are lower than others vindicates their approach.
They say it’s important because the difference between a 20% tariff and a 10% tariff is thousands of jobs.
Where to next? No 10 says it will “keep negotiating, keep cool and calm”, and reiterated Sir Keir Starmer’s desire to “negotiate a sustainable trade deal”.
“Of course want to get tariffs lowered. Tomorrow we will continue with that work,” a source added.
Another source said the 10% tariff shows that “the UK is in the friendlies club, as much as that is worth anything”.
Overnight, people will be number-crunching, trying to work out what it means for the UK. There is a 25% tariff on cars which could hit billions in UK exports, in addition to the blanket 10% tariff.
But despite this being lower than many other countries, GDP will take a hit, with forecasts being downgraded probably as we speak.
I think the government’s approach will be to not retaliate and try to speed up that economic deal in the hope that they can lower the tariffs even further.
There will be concessions. For example, the UK could lower the Digital Services Tax, which is imposed on the UK profits of tech giants. Will they loosen regulation on social media companies or agricultural products?
But for now, there is relief the UK has not been hit as hard as many others.
Liberal Democrat leader Sir Ed Davey has reacted furiously to Mr Trump’s announcement of a “destructive trade war”, and called on the government to stand up against “Trump’s attempts to divide and rule”.
“The prime minister should bring our Commonwealth and European partners together in a coalition of the willing against Trump’s tariffs, using retaliatory tariffs where necessary and signing new trade deals with each other where possible.”
Speaking on Wednesday evening at a White House event entitled ‘Make America Wealthy Again’, the US president unleashed sweeping tariffs across the globe.
Mr Trump held up a chart detailing the worst offenders – which also showed the new tariffs the US would be imposing.
The UK’s rate of 10% was perhaps a shot across the bow over the 20% VAT rate, though the president’s suggested a 10% tariff imbalance between the two nations. Nonetheless, tariffs of 10% could directly reduce UK GDP by between 0.01% and 0.06%, according to Capital Economics.
A 25% duty on all car imports from around the world is also being imposed from midnight in the US – 5am on Thursday, UK time.
The UK government had been hoping to negotiate an economic deal with the US in a bid to avoid the tariffs, but to no avail. The government says negotiations will continue.
The Confederation of British Industry said “negotiating stronger trading relationships with all like-minded partners will be foundational to any success”.
The business secretary is expected to make a statement in the House of Commons on Thursday, and we are also expecting to hear from the prime minister.