MP says 'junk science' of lie detector tests used on sex offenders is risk to victims

The number of lie detector tests being used on sex offenders in England and Wales has almost tripled in the last three years, leading to fears that victims’ safety is being put at risk.

- MAYA OPPENHEIM

The controversial tests are being used on prisoners out on licence, and are taken into account when deciding the level of restrictions put in place or whether someone should be put back behind bars. But their validity is highly disputed among scientists and evidence produced using them is not admissible in the UK’s criminal courts. One MP condemned them as “junk science”.

Data obtained by The Independent under freedom of information laws reveals that the number of lie detector tests used by the probation service on sex offenders rose from 634 in 2020 to 1,797 in 2023.

The tests measure physical reactions such as breathing, sweat levels, and blood pressure to see if someone is telling the truth. Offenders could be asked whether they have had contact with children or are going to prohibited locations in sessions that can last up to more than four hours.

One of the reasons for the rise in lie detector tests is thought to be sentencing changes introduced by the Tory government, which resulted in more sex offenders being let out on licence.

Labour MP Kate Osborne, who sat on the Women and Equalities Committee until the election, said the use of lie detectors must not be “normalised”, warning they can enable sex offenders to manipulate the system.

The MP for Jarrow and Gateshead East said: “Lie detector tests are completely unreliable. It is appalling that they are being used in sex offence cases. This junk science puts women and victims at risk.”

Lie detectors have been used to monitor high-risk sex offenders released on licence since 2014 but have also started being used on terrorists and domestic abusers in recent years.