I saw Tim Lott on tv once, he was taking part in a discussion on one of those arts review programmes. He dominated the argument, talking forcefully, almost agressively. Armando Iannucci was there (seemed a bit unsure of himself) and also Andrew Davies. Davies was Lott's main opponent, but no match for him.
In The Seymour Tapes, Lott writes about a bloke who secretly films his family. At one point he had a dilemma in that he saw a misdemeanor by his child, but couldn't confront him with the evidence because that would reveal how he obtained it.
This is similar to the government's problem with phone tap evidence. In the government's case they should either do nothing, or they should go ahead and present the evidence.