Let's take a look at some recent cases:
The prosecution of Paul Chambers: This is probably the most famous recent case. Paul Chambers, upset that Robin Hood airport was closed, vented his frustration on Twitter with the tweet:
Crap! Robin Hood Airport is closed. You’ve got a week and a bit to get your shit together, otherwise I’m blowing the airport sky high!!. Despite the fact, as laid out in Jack of Kent's excellent blogpost, that neither the airport nor the Police considered his tweet to pose any credible threat, he was charged by the CPS, and prosecuted.
The imprisonment of a rape victim: A woman was jailed for falsely retracting a statement she had made, in which she claimed she had been raped by her husband. To put it a bit more clearly, she was jailed because she had been raped, and then "emotionally blackmailed" by her husband into retracting the statement, wasting the CPS's valuable time and money that could be spent prosecuting people on Twitter. Remarkably, the judge who handed this sentence down has offered less severe sentences to people who download child pornography or beat their wives.
The CPS trying to sue someone for kidnap with no grounds whatsoever: Only one source for this one, but if it is true then it is yet another brilliant use of resources by the CPS, which are, of course, finite, meaning that they can't always prosecute over insignificant little events like...
The Death of Ian Tomlinson: How there can be no case here? There is video footage of a policeman pushing a man to the ground, a man who was walking away with his hands in his pockets. Whether or not this caused Mr Tomlinson's death, there should be enough to show that wrongdoing is in place. The anger I felt at the CPS's decision here cannot be overstated. I was immediately reminded of this case after the CPS's most recent decision, and it troubles me that serious crimes are potentially going ignored, whilst trivial events and victims are being attacked.
I am, of course, aware of the fact that many guilty people are sentenced correctly, and many innocent people let off. I am aware that there are far worse legal systems out there, and that my increasing interest in politics over the last few years has increased my exposure to these instances of injustice. But the illiberal judgements and questionable prosecutions, or lack thereof, are overpowering any faith I once had in the police, the CPS and the organisations that are supposed to be there to protect me, and society.