Home Affairs Correspondent
Doubts were cast yesterday on the merits of a controversial "degrading" test for sexual deviancy in which prisoners watch explicit videos or pictures with electronic sensors fitted round their penises.
The Prison Reform Trust called for an urgent independent review of the test which forms part of a programme to assess prisoners as potential sex offenders and can influence decisions over their release.
The Penile Plethysmograph or PPG is a mercury-filled loop which is placed around the penis and detects even small changes in the amount of blood supply that may occur in men shown various images or played a variety of audio-tapes.
It has been used widely in the US and the UK, and is currently performed in nine prisons in England and Wales on about 100 prisoners a year - usually known sex offenders - to see if they should attend the Sex Offender Treatment Programme.
A report by the trust says the test has not been proven as a reliable indicator of sexual offending. There is also concern about its use on life-sentence prisoners who have not been convicted of any sex crime, and that it amounts to a breach of civil rights.
The Prison Service said yesterday that the latest research from the US and Canada found the test "one of the most reliable psychological correlates of sexual offending".
However, Ronald Blackburn, a forensic psychiatrist at Ashworth Special Hospital, Liverpool, says in his recent book, The Psychology of Criminal Conduct, that it only assesses one component of sexual arousal, but not sexual behaviour itself. "Its use as a sexual lie detector or to forecast dangerousness is not warranted since its predictive utility has not been unequivocally demonstrated and there are recent debates about the limits of its utility." He added that it is only a useful measure of paedophile interest - not for rapists.
Maurice Lipsedge, consultant psychiatrist at Guys Hospital, London, said: "I believe the technique has its limitations when it comes to predicting further offending. Neither should it be used in isolation."
Andrew Groves, author of the report said: "If this test can be proven to be successful a successful predictor of behaviour, then the public ought rightly to be interested. However, we all have our fantasies and the fact that a test can demonstrate or show up what those fantasies of predilections are doesn't mean that we are going to translate them into action or reality.
"Where there is doubt about the efficacy of the tests, and where it is not clear to the public what function it serves, then this would appear to be a degrading breach of human rights."
tA Suitable Case for Treatment; Prison Reform Trust; 15 Northburgh Street, London EC1V 0AH; pounds 2.50.Reuse content