Literally copying the literal Stasi approach to spying (not the rest, just spying) would simultaneously improve the quality of the data and reduce the negative side effects relative to the UK’s Investigatory Powers Act 2016.
By definition, in their line of work if you knew exactly how useful and effective they were they would not be doing their job properly. They report to the UK government, not to you and not to me even though I am a UK citizen (as you may be, I don't know). They have worked for governments lead by or including all three main political parties in the UK and they all decided they were useful enough to them to keep, in pursuing their goals on behalf of the people who elected them. That's good enough for me.
But we do know how effective they aren't. And we do know that they have placed themselves above the law. If that doesn't concern you it really should.
The macho pose that comes out everytime someone suggests they should be subject to, you know, the law and behave better than Stalin's henchmen is very worrying.
So who is the politician who will is effective enough to provide true oversight and rein them in when required.
