There are two elements, as I understand it, where polygraphs are introduced: one is in licence conditions and the other is the use of TPIMs. I can certainly talk about the latter, but maybe not the former.
It is safe to say that the science around polygraphs is not absolutely fool-proof. For that reason, we and the CPS agree that we would never seek to use them as evidence in a criminal prosecution in the UK. By introducing polygraph measures in these circumstances—in TPIMs—you may end up with that evidence through disclosure, not for criminal prosecutions.
The reality is that polygraphs are untested in the terrorist space, but we would welcome the ability to pilot them. We would not necessarily be seeking mandation on every single TPIM. It says “if required”, and again that should be an operational decision for us. They are untested, which is why they are not used in criminal proceedings. They have utility in the management of sex offenders, as Jonathan pointed out, and they may well have utility in the management of terrorist offenders. We would be happy to try that and see where it takes us.