London Telegraph 
July 31, 2012
Polygraphs, the lie detector machines beloved of Fifties comic books and Jeremy Kyle shows, have a chequered history. American law‑enforcement agencies continue to use them, despite what critics claim is a lack of evidence that they actually work.
Now our Government has announced plans to use them to help determine whether or not paedophiles and rapists should go back to jail.
The Ministry of Justice will allow probation officers to send paroled sex offenders back to prison  if a polygraph finds they have been lying. This follows a pilot study by the University of Kent  which found that offenders were twice as likely to offer “clinically significant disclosures” – such as an admission of entering an exclusion zone around a school – if they were subjected to polygraph tests.
This is the latest example of British law-enforcers adopting technologies and methods that many deride as flawed at best, pseudo-science at worst. Graphology (the study of handwriting to reveal personality), voice-stress analysis, even “mind-reading” magnetic resonance imaging (MRI) machines: all have been posited as methods for sorting the honest from the deceitful. And it is not just the police who have been seduced by these devices; the Department for Work and Pensions has used voice analysis in an attempt to detect benefits cheats.