Sex offenders across the UK are currently undergoing lie detector tests for a pilot scheme.
The lie detector trials will be conducted in 10 different areas
The trials, which cover 10 different parts of the country, aim to ensure sex offenders are not breaking the terms of their release.
A pilot scheme was launched in three areas of the country in 2002 and has now been expanded.
It was credited with helping to prevent sex offenders from re-offending after release from prison.
Newcastle University professor Don Grubin was responsible for conducting the study.
"The interesting thing we found was that the probation officers thought that the 32 volunteers who took part, were doing well before the tests," he explains.
"But when we tested them with polygraph machines, all but one of them disclosed information which was a concern.
"Up to a third of them also admitted to having unsupervised contact with children.
"I am confident we prevented three offences because of these tests."
Following the results, the Home Office decided to take a closer look at the pilot scheme and it widened the scale of the research.
The latest scheme started last September and around 300 volunteers will take part in the trials over a two-year period.
Prof Grubin says: "The current scheme has been very successful so far because we have had a lot of interesting disclosures.
"A lot of the volunteers have passed which has proved very reassuring to the probation officers."
Lie detectors, work by measuring a person's unconscious physiological reactions to questions that are put to them by an examiner.
The volunteer has to wear two bands across his chest to measure breathing, a cuff around his arm similar to the one used to take the pulse and two finger cuffs to measure sweating.
Through heart rate, blood pressure, respiratory rate and sweatiness, the examiner determines whether a subject is answering truthfully.
According to the Home Office, testing may help offenders to be more open and honest with probation staff.
As a result, they could then be in a better position to manage offenders' behaviour and help them to avoid situations where they might be at risk of reoffending.
"The interesting thing about polygraph machines is that they do not stand on their own as a tool .
"When they are combined with other methods such as satellite tracking, they could prove to be very effective," Prof Grubin added.