Are lie detector tests for terrorists really a good idea?

You might have assumed that the polygraph (or ‘lie detector’ as it is commonly known) was something used only for entertainment on the Jeremy Kyle Show. It is, after all, little more than a relic from the 1920s when people turned to psychic mediums and truth-telling machines in the misguided search for certainty after the horrors of the Great War. So it might come as a surprise that the polygraph has been used by the penal system in England and Wales for more than a decade. The Probation Service, in fact, uses them to monitor sex offenders released on licence. In the past five years alone, 5,228 mandatory polygraph examinations have been carried out on 2,249 sexual offenders, according to the Home Office.

Few people are likely to be concerned about their use on sex offenders; anything that could prevent re-offending is probably assumed to be a good thing. However, there is a new development when it comes to polygraphs that should worry everyone who cares about due process.