My Lords, I have many reservations about the value of polygraph tests. They rely on measuring several physiological processes—pulse rate, blood pressure, perspiration and so on, the changes that may take place in the course of questioning. However, the emotional and physiological responses recorded may arise from such factors as simple anxiety about being tested or fear of being judged deceptive, or a host of things—perhaps the state of one’s digestion after food. There is an inherent ambiguity in the physiological responses. The reluctance to use polygraph evidence is precisely because the response may mimic the response expected of a person seeking to deceive.
What is meant by “failing” the polygraph test? Failing the test means exhibiting a certain physiological response to a question. What is truth? The examiner cannot know whether that response means that the answer is a lie. However, there is no punishment for failing the test—whatever that means—or for exhibiting that response. That does not breach the terms of the offender’s licence. The individual will not be returned to prison. Alterations may, however, take place in the conditions of his licence, and those could be onerous.
The irony is that, in the course of questioning, the person being questioned may provide information truthfully that will have an adverse effect on him. He has not failed the test because his body does not react to his telling the truth, but he has provided information that may lead to his punishment. He has of course lost his right to silence, a right first developed in the late 17th century as a check to arbitrary rule. It has been regarded over centuries as fundamental to the fairness of the criminal law in this country and in the common-law countries all over the world.
Faced with the terrorist atrocities that we have seen in this country, the loss of the right to silence may seem a worthwhile price. Obviously that is not the immediate view in Scotland, nor in Northern Ireland. Let us face the dilemma: the proposals for England and Wales do not involve imprisonment for a lie but possible imprisonment for telling the truth or, since it is mandatory to answer the questions, even for remaining
silent. Faced with legal and moral issues such as this, the drafters of the Domestic Abuse Bill, which is proceeding this week here also, as the Minister will know, decided that it was appropriate to proceed with a three-year pilot before finally rolling out the use of polygraphs generally in that field. Why is a different approach taken in this concurrent Bill?
It is interesting to note that the case studies in the MoJ memorandum on these proposals indicate that the information provided led to warrants being issued and physical evidence obtained in the offenders’ respective homes to contradict what they had said. However, there is no indication how often that has occurred or how many times such activity has proved nothing, and nothing has come of it. Will the Minister deal with that in his reply?