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.

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