Thanks for your reply and explanation of how that works.Yes, judges can authorise listening devices and other investigation methods that would otherwise be unlawful. Police have to explain to the judge why they believe it is necessary and if the judge agrees, then it can be done. But it’s always a very specific authorisation. I was involved in one case where police asked for warrants for several listening devices between various parties. Some, but not all, were granted. The judge didn’t think there was enough reason for all of the ones requested.