Essex Police Detective Chief Inspector Jim Sandford said: “We use the polygraph test to get information about whether or not a sex offender is reoffending, so that we can assess the risk they pose to the public and ensure they are complying with sexual harm prevention orders imposed by the courts.
“We can’t force people to take part unless it forms part of a court order and the results of a polygraph test can’t be used as evidence in court.
“But the benefits are that it shows they are willing to engage and cooperate with the authorities, and it can prevent us relying on more intrusive methods of monitoring.
“The polygraph examination itself is carried out in three stages, with an interview, followed by the polygraph test and a post-test discussion.
“We have seen some participants tell us about reoffending during the pre-test interview and others make admissions after undergoing the polygraph.
“We have had occasions where offenders have admitted further offences or breaches of preventative orders, which have triggered investigations that are ongoing.
“We have also seen some admit that they may have potential contact with children, which has allowed us to directly intervene and keep people safe.”