Lie-detector tests are being used to gauge the truthfulness of suspected child sex offenders and help establish if they warrant further investigation.
In a trial being run by Hertfordshire police, 25 sex offenders deemed to be "low risk" were asked to take the tests.
Of the first 10 analysed, six revealed behaviour more serious than they were suspected of and were investigated in more detail. Two more made disclosures that they later refused to admit in a formal interview. Results of the tests are not admissible in court as evidence, but the Government recognises the potential of polygraph testing under certain controlled conditions and it is expected to be introduced more widely if tests prove successful.
The trial is being overseen by Professor Don Grubin, a forensic psychology specialist at Newcastle University. According to a report last night, he said that lie detectors could help to make sure offenders did not "slip through the net".