In a spirit of fairness, and having once had to deal with this kind of thing as a civil servant (though not in the intelligence area, thank goodness) I thought I’d actually put in a good (or at least mitigating) word for GCHQ.
You’ll have seen the Guardian story, based on some of Edward Snowden’s revelations, suggesting that GCHQ opposed the use of intelligence in criminal trails because, in the newspaper’s words it “could lead to legal challenges against its mass-surveillance programmes.”
There are, in fact, a number of reasons why the use of intelligence material in criminal trials is problematic. As well as threats to sources and methods (criminals are not entirely stupid, and would no doubt adapt) there’s the simpler and more basic fact that much, if not most, intelligence material is actually not very useful as evidence, and doesn’t actually help to establish a criminal level of proof. Intelligence isn’t intended for that; it’s intended to guide and nudge, and to fill in gaps with the best information you can manage to get. It also often means very little outside a context you are already familiar with. A scrappy conversation in heavily-accented West African French between two individuals who don’t identify themselves but talk about a “cargo” going “north” – well, you get the drift. For this reason, most intelligence material is actually pretty banal and mundane when taken out of its brightly coloured folders and seen for what it is. It’s no wonder politicians are often a bit disappointed when they see intelligence material for the first time (you mean this is it…?)
I see that quite a few people got the wrong end of the stick about the “legal challenges” bit as well. It doesn’t mean that what GCHQ were doing was illegal, or that they thought it was. The British system doesn’t work like that, or at least it didn’t. What it means that a clever defence lawyer defending, say, a group of accused fraudsters, would try to get any intelligence evidence ruled out of court by using some such device as the European Convention on Human Rights, and probably get the government to abandon the trial rather than have to give all sorts of sensitive information about the how and the why of surveillance. “Legal challenge ” these days means “using the law as a weapon”. It doesn’t unfortunately have anything to do with guilt, innocence or the merits of the case.
There, you see. Not everything GCHQ say is wrong.