Kyriakos Kotsoglou on Polygraphs in the British Legal System

Kyriakos N. Kotsoglou (Twitter profile)

In episode 102 of the legal podcast Excited Utterance, Vanderbilt University law professor Edward K. Cheng (@edwardkcheng) interviews Northumbria University senior lecturer in law Kyriakos N. Kotsoglou (@Kyri_Kotsoglou) about the use of polygraphs in the United Kingdom, with an emphasis on Kotsoglou’s new article, “Zombie Forensics: the use of the polygraph and the integrity of the criminal justice system in England and Wales,” International Journal of Evidence and Proof, 2021 (1): 16-35.

Edward K. Cheng (Twitter profile)

Kotsoglou addresses the systemic problems associated with a justice system embracing such a pseudoscientific technique as polygraphy. His critique is of relevance for policymakers everywhere.

The Guardian’s Ian Sample on Polygraph Use by the British Ministry of Justice

The Guardian’s science editor, Ian Sample, sits for a polygraph “test” and reports on the British Ministry of Justice’s growing reliance on the pseudoscience of polygraphy. Excerpt:

The Ministry of Justice introduced compulsory lie detector tests for sex offenders in 2014. But now the controversial technique is poised to become more widespread in the British justice system.

The domestic abuse bill and the counter-terrorism and sentencing bill, both passing through the Lords, provide for regular, mandatory testing of domestic abuse offenders, suspected terrorists and convicted terrorists on release. While failing a test would not in itself mean prison time, fresh disclosures, investigations prompted by failed tests, attempting to beat the polygraph, refusing a test or remaining silent in a test, could all trigger a recall. Loss of liberty in such circumstances is determined not by court but by probation officers, the former lord chief justice, Lord Thomas, has noted. Tests are expected to start in the spring.

For Don Grubin, emeritus professor of forensic psychiatry at Newcastle University and director of Behavioural Measures which runs the Heaton Mount training course, the polygraph is a means of gaining fresh information, an additional tool to help manage offenders. “What you’re looking for is information to indicate there’s an increased risk,” he says. But debate in the Lords and beyond has raised serious questions around the polygraph’s place in the legal system.

Marion Oswald, vice-chancellor’s senior fellow in law at Northumbria University calls the polygraph “an oppressive interrogation tool”, a phrase Grubin finds “over the top”. Oswald wants an immediate moratorium on polygraphs, an independent review of their usage across police forces and the probation service, and if tests resume, continuing independent oversight. “There’s a really high risk of people relying too much on these polygraph outputs,” she says. But Grubin argues there’s no evidence of this being an issue, adding that the risk is no greater than for other measures, such as criminal record checks and tagging.

It is not “over the top” to characterize the polygraph as “an oppressive interrogation tool.” It is precisely that. Indeed, former police polygraph operator Doug Williams has aptly characterized the polygraph as a “psychological billy club.”

Because polygraphy has no scientific basis, any reliance on polygraph chart readings is over-reliance.

British Charity Calls for Polygraph Testing of Pedophiles

BBC News reports on a call by the charity, Barnardo’s, for lie detector testing and GPS tracking of pedophiles in the UK. Excerpt:

Children’s charity Barnardo’s is calling on the government to use lie detector tests and satellite tracking to monitor sex offenders.

It claims pilot studies in the UK have shown promising results.

One such trial found up to 80% of cases showed lie detector tests revealed new information about the offenders’ intentions or behaviour.

Barnardo’s says this helps probation staff assess the risks they pose when they are released from jail better.

Barnardo’s make the claims in its new report, entitled A Risk Too Far? which is published on Tuesday.

It also says such measures will be more effective than the introduction of the proposed Sarah’s Law, which would allow parents to learn of registered sex offenders living in their area.

This is because it believes such a law would drive sex offenders away from supervision and into hiding.

‘False comfort’

This proposed legislation is named after eight-year-old Sarah Payne, who was murdered by paedophile Roy Whiting in 2000.

Barnardo’s chief executive Martin Narey said: “Barnardo’s is committed to protecting children from harm, but we feel that a Sarah’s Law would offer a false comfort to parents and could put children in more, not less, danger.

“That said, the current arrangements for the safe supervision of dangerous offenders need to be strengthened and public confidence restored.

“Our report outlines how the use of polygraphs and satellite tracking could radically improve the effectiveness of supervision.

“All the indications are that polygraphs can be effective in helping control behaviour.

“I have personally seen their use on sex offenders, spoken to the probation staff who have used this technology in a pilot [study] in the North East, and been impressed by the officers’ conviction that it significantly improves the rigour of supervision.”

But human rights group Justice questioned the effectiveness of lie detector tests.

“We’re very doubtful as to any evidence that’s been produced to show that it’s a reliable method,” the group’s policy director Eric Metcalfe told BBC News.

“In our view, this kind of measure has more of a headline effect than actually being demonstrated to be genuinely effective.”

Eric Metcalfe has it right about lie detectors. Regarding British proposals for polygraphing sex offenders, see Dr. Drew C. Richardson’s 21 May 2005 letter to the Telegraph. Barnado’s express concern about policy measures that would provide a false comfort, yet only a false comfort can result from relying on such a widely discredited procedure such as polygraphy. Make-believe science yields make-believe security.

UK: “Lie-Detector Tests for Sex Offenders”

The Telegraph reports. Excerpt:

Sex offenders will face compulsory lie-detector tests, the Government has announced.

Ministers want to use polygraph tests on sex offenders who have been released from jail on licence.

The move will ensure they are telling the truth about their behaviour, such as obeying bail conditions to keep away from schools and playgrounds.

The idea has been piloted on a voluntary basis in 10 areas across England but it will now be extended under a new Management of Offenders Bill on a compulsory basis.

UK: “Paedos ‘Can Beat Lie Test'”

Don Mackay reports for the Mirror:

PAEDOPHILES and other sex offenders could fool lie detector tests, experts warned yesterday.

As part of bail conditions the Home Office is drawing up plans to use polygraphs to monitor whether sex offenders will strike again.

But the British Psychological Society said the tests could be beaten – and are anyway far from accurate. One study of polygraph techniques used in criminal probes found up to 17 per cent of guilty suspects “cheated” and were found innocent, while as many as 47 per cent of innocent suspects were classed as guilty.

Tests are based on physical responses – such as increased sweating, heart-rate, blood pressure and respiration – to questions.

But the BPS found subjects could suppress their reactions.

Professor Ray Bull of Leicester University, who chaired the working party, said: “We must not deceive ourselves into thinking there will ever be an error-free way of detecting deception.””

A Home Office spokesman said polygraph tests on sex offenders and others were still at the pilot stage.

He added: “We have found tests encourage offenders to disclose previous offences and current behaviour.”

UK: “Sex Offenders Face Lie Detector”

BBC News reports. Excerpt:

Convicted paedophiles would face mandatory lie detector tests in parts of the UK under plans put forward by the government.

The measure is in the Management of Offenders and Sentencing Bill, which was published on Thursday.

The Home Office says 148 tests have been carried out on sex offenders since a pilot scheme began in September 2003.

The bill also contains plans to allow private companies to supervise offenders on community sentences.

The use of lie detector – or polygraph – tests has been piloted in areas across the UK, including Lancashire, Manchester, Devon and London, on volunteers.

Under the proposals, the tests would become mandatory in the pilot areas.

They could be used to help monitor behaviour, such as whether sex offenders are keeping bail conditions to stay away from schools.

The Home Office will see how the tests work in the pilot areas before deciding whether to use them nationwide.

A spokeswoman said: “Protecting the public is our priority. We have a responsibility to keep abreast of modern technological developments to see how they can help us.”

The polygraph is not a “modern technological development.” Rather, as Professor John J. Furedy has put it, it is a “technological flight of fancy” that is “founded on lies.”

UK: “Sex Offenders Forced to Face Lie-Detector Tests Upon Release”

Independent crime correspondent Jason Bennetto reports:

Sex offenders living in the community are to take compulsory lie-detector tests after a study found 85 per cent were reoffending or breaching parole, or had failed polygraph tests.

The Home Office intends to introduce a law to force those offenders released from prison under community and probation orders to take the tests. The move is understood to be part of a pilot study included as a clause in the planned Management of Offenders and Sentencing Bill in the coming year.

The police are also considering using polygraphs to help monitor sex offenders and have discussed deploying them in cases involving domestic violence and stalking.

The controversial polygraph tests, which are considered to be 90 per cent accurate, can detect when people are lying by measuring changes in breathing, heart rate and sweating.

The move towards a compulsory system follows the results of the continuing pilot study in which 200 convicted sex offenders, who are mostly paedophiles but include some rapists, have volunteered for tests. The results, which were disclosed to The Independent, revealed that 85 per cent either failed or disclosed information about reoffending, breaching the conditions of their community orders, or were experiencing deviant behaviour involving children. Within the 85 per cent, about two-thirds made disclosures of information that had not been known to their probation officers. About 20 per cent failed the polygraph test without making a disclosure, but revealed information that needed further investigation.

The testers were not allowed to ask the sex offenders whether they had reoffended, but some volunteered the information, including one man who admitted having sex with an underage victim.

At first the new power for compulsory tests will be used in the project in which a total of 200 sex offenders have so far undergone a polygraph test. If this study is successful, the mandatory scheme is expected to be adopted nationally. The Probation Service, which along with the Home Office and police has been exploring the use of polygraphs, is enthusiastic about the use of lie detectors in managing sex offenders. The National Probation Directorate is drawing up plans for a possible regulatory body that could oversee the training and qualifications of polygraph testers.

Don Grubin, professor of forensic psychiatry at Newcastle University, who is leading the polygraph study, said: “We have discussed the use of polygraphs with the police.

“They are not using it at the moment, but are interested in trying it out in certain situations. They have indicated that it could be used in managing sex offenders, cases of domestic violence and people with a history of stalking. They are reluctant to use it in a criminal investigation, but I think there is some potential there.”

Professor Grubin described the results of the current tests as “startling”. “Most of these guys who are put before the polygraph just admit it all.” Asked why offenders who were breaking their release conditions would volunteer to take a lie test, he replied: “There are some who want to prove they are low risk and think they can beat the polygraph.” It can also be used to show that a former offender is sticking to his treatment and is no longer a danger.

In July last year Home Office and police representatives visited the FBI in Washington, the Department of Defence in Fort Lauderdale, Florida, and a private polygraph-testing centre to investigate lie detectors, which are widely used in the US.

Liz Hill, the head of public protection at the National Probation Directorate, who is overseeing the tests for the Home Office, said: “One of the things we learnt was that if you are going to go down this route you need a regulatory body.”

The UK agencies involved in developing lie detectors have said the test can only be used as an indicator. The machines would not be used to gather evidence to be used in court.


The creator of the comic strip character Wonder Woman also invented the first lie detector, or polygraph.

But the original device, unveiled by the psychologist William Marston in 1917, was widely criticised and has been replaced by far more sophisticated techniques.

Polygraphs are being used in a UK pilot study of 200 male sex offenders in nine regions around England. The Home Office believes they could be a useful tool in managing sex offenders.

The test measures changes in the rates of breathing, sweating and heart activity. The subject has tubes going round his chest and abdomen to measure breathing. Blood pressure is also recorded, and two flat rods are stuck to the subject’s palm and finger to measure sweating.

These calculations indicate arousal in the subject. The theory behind the polygraph is that arousal is a non-voluntary part of the nervous system. If the subject’s response pattern is greatly altered then it indicates that they are lying.

The sex offenders take up to three sets of questions, to which the answer is yes or no. One test is “sex history disclosure” in which the offender is questioned about victims and other behaviour. The “maintenance test” involves the offender being questioned about whether he is sticking to conditions of parole. Under the “specific issue test”, the subject is questioned about aspects of an offence that they are denying. Only about 15 per cent of the offenders taking part in the British trial passed their polygraph test first time.

The claim that lie detectors “are considered to be 90 per cent accurate” is one that is only being made by those with vested interests in promoting polygraphy, and flies in the face of the broad consensus amongst scientists that polygraph “testing” has no scientific basis. The claim that William Marston’s polygraph technique “has been replaced by far more sophisticated techniques” is also misleading. The “control question test” that is the standby technique of the polygraph community can hardly be characterized as “sophisticated.” On the contrary, it is highly simplistic and easily thwarted by the use of simple countermeasures that polygraphers cannot reliably detect.

UK: “Lie Detectors Will Be Used to Catch Benefit Fraudsters”

Nigel Morris and Ben Russel report for the Independent on secret UK government plans to use voice stress analysis to evaluate work-related claims:

Secret plans by the Government to use lie detectors to weed out fraudulent benefit and compensation claims were last night condemned as an invasion of privacy.

Ministers are examining whether to adopt a controversial technique recently adopted by insurance companies to catch bogus claimants.

Government documents obtained by The Independent show both the Department of Trade and Industry (DTI) and the Department for Work and Pensions (DWP) are considering proposals to monitor telephone calls from the public to detect signs of stress in the voice that can betray false claims.

The move was condemned by opposition MPs, who attacked lie detector technology as unreliable and said it was no basis for determining the honesty of claimants.

DTI documents have privately acknowledged that using the technology could be “presentationally very sensitive” and should be kept secret for the moment.

The plan has been drawn up by DTI civil servants handling a scheme awarding compensation to miners who suffer vibration white finger, which is caused by working with chainsaws and drills.

The biggest scheme of its kind in the world, a large backlog in dealing with claims from former miners and their families has built up. About 600 cases of suspected fraud are being investigated by an insurance company employed by the DTI to assess the claims.

A memo to Nigel Griffiths, a trade and industry minister, says: “Using this technology is likely to be presentationally very sensitive if, after the pilot, we do go ahead. However, we think it is worth looking into it.”

It discloses that the DWP is also looking at the same technology, but tells ministers that if the lie detector technique is used “it will be the first time this method is put into practice in the private sector”.

It urges ministers to hold a pilot in absolute secrecy and not to tell solicitors who are representing claimants.

Mr Griffiths is understood to be strongly resisting the proposal, while the DWP denied that it was considering using the technology. A spokesman said the department “has no plans” to use lie detectors. The technology could be used both for miners who make claims and their families and helpers.

But Steve Webb, the Liberal Democrats’ work and pensions spokesman, expressed concern abut the technology’s use in the benefits system. He said: “These things are black boxes. How can you appeal against the decision of a black box? People’s cases should be determined on the individual facts.”

UK: “Plans for Paedophile Lie Tests”

The BBC reports:

Convicted paedophiles could be forced to take lie detector tests to ensure they stay away from children, under plans by Home Secretary David Blunkett.

He wants compulsory testing in Sussex, Northumberland and the West Midlands – currently piloting voluntary tests.

Probation officers would ask offenders whether they had had contact with children since their release from jail.

But reports suggest there is concern among some Cabinet members over the use of the US-style polygraph test.

‘Ensuring public safety’

A Home Office spokeswoman said the tests would accompany other methods, such as electronic tagging, to monitor the behaviour of offenders following their return to the community.

The Home Office spokeswoman said: “(Lie detector) testing is carried out purely on a voluntary basis in the pilots.

“We are not talking about a countrywide expansion of the scheme.

“What we are looking for now is to make these pilots mandatory so that we can fully assess the effectiveness of lie-detector tests in helping to monitor sex offenders and ensure the safety of the public.”

I accept that this is not without controversy. Given the controversial nature of these proposals, I am consulting Peter Goldsmith

Mr Blunkett has told the Cabinet he is hoping to bring in legislation to extend the current voluntary trial in several parts of England.

But reports on Sunday suggested that the proposal to move from voluntary to compulsory testing had sparked concern in the Cabinet.

The Sunday Times quoted Trade Secretary Patricia Hewitt – a former head of the National Council for Civil Liberties – as requesting “further evidence” before a decision is reached on whether to push ahead with the necessary legislation.

Polygraphs – which measure changes in breathing, heart-rates and sweat in response to questioning – are considered to be only around 90% accurate, which could lead to fears over their authority in cases of increased monitoring or tagging of paedophiles.


Mr Blunkett is reported to have accepted his proposals are “not without controversy” and to be consulting Attorney General Lord Goldsmith on the legal implications.

Tests would not be used to gather evidence for court cases and offenders would not be returned to jail purely on the basis of polygraph results.

It is believed that the prospect of compulsory tests would act as a deterrent against breaches of offenders’ terms of release.

The Sunday Times report includes extracts from what it says is a leaked letter from Mr Blunkett to Deputy Prime Minister John Prescott on 20 July.

The Home Secretary asks for Cabinet approval for legislation, which he said would be “an additional weapon in the armoury against sex offenders”.

Contact with children

He added: “I accept that this is not without controversy. Given the controversial nature of these proposals, I am consulting Peter Goldsmith.”

So far voluntary trials in Northumberland, the West Midlands and Sussex have reportedly been judged a success.

In one trial, 32 offenders volunteered for tests and a third admitted having unsupervised contact with children, according to the Sunday Times.

The BBC is mistaken in reporting that polygraphs “are considered to be only around 90% accurate.” In fact, it’s much worse than that: there is broad consensus amongst scientists that polygraph “testing” has no scientific basis. And it has not been proven through peer-reviewed research to reliably work at better-than-chance levels under field conditions.

UK: “Lie Detector Plan Worries Cabinet”

Home affairs editor Alan Travis reports for the Guardian.

Home Office plans to introduce compulsory lie detector tests to ensure that convicted paedophiles do not offend again are worrying cabinet members.

The home secretary, David Blunkett, has admitted to his cabinet colleagues that the plans “are not without controversy” and is seeking legal clearance from Lord Goldsmith, the attorney general.

A leaked ministerial letter dated July 20 shows that Patricia Hewitt, the trade and industry secretary, a former head of the National Council for Civil Liberties, wants “further evidence” before a decision is reached this summer to push ahead with the necessary legislation.

Mr Blunkett has asked the cabinet to approve the plan, describing the polygraph tests as “an additional weapon in the armoury against sex offenders”.

When the Guardian disclosed the scheme in May the human rights organisation Liberty, the NCCL’s successor, said it would raise no fundamental objections as long as the results were not used in court as evidence and would help prevent reoffending.

The shadow home secretary, David Davis, has also said their use could be beneficial.

The American polygraph technology is being considered alongside the introduction of satellite tracking of convicted sex offenders to monitor their behaviour after their release on licence from prison.

A voluntary two-year trial in 12 of the 42 probation areas, including Northumbria, the West Midlands and Sussex, is understood to have been judged a success. It has involved 120 convicted sex offenders, who have been tested every six months.

Five polygraph machines have been used in the trials. They measure changes in breathing, heart rate and sweat in response to questioning, and officials believe they can be used to establish, along with other evidence, whether convicted sex offenders are telling the truth about whether they have been trying to contact children.

“We’re not talking about a countrywide expansion of the scheme,” a Home Office spokeswoman said yesterday.

“What we’re looking for now is to make these pilots mandatory so that we can fully assess the effectiveness of lie detector tests in helping to monitor sex offenders and ensure the safety of the public.”

She stressed that the tests would not be used to gather evidence admissible in court, which is the source of much of the controversy surrounding their use in the US.

Nor will anybody be sent back to prison solely on the evidence of the results of a polygraph tests. “They are being used only as a limited management tool to support a range of other methods employed to monitor and supervise sex offenders,” the spokeswoman said.

Mr Blunkett has acknowledged the controversial nature of lie detector tests before.

“We are all a bit sceptical, because we’ve all been brought up with the spy films and the way in which the KGB are allegedly able to train people to avoid them. But we are talking about really modern technology in the 21st century, and we are testing it,” he said when he launched the idea in June.

“It won’t only just pick up whether a person is lying, it will also be a major deterrent to people actually telling an untruth when they are under supervision and when it is necessary to find out what they’ve been up to.”