TAE said:
I was not suggesting the police should do nothing unless they have absolute proof, I was speculating that pressure might be put on the police by the government to intervene when there is not really sufficient grounds even for a reasonable suspicion.
I can see why you were not a detective because you seem to find it impossible to (a) accept that there may be situations between two extreme poles; (b) accept that there may be cases in which the absence of sufficient evidence to convict does not necessarily mean that there was not actually a conspiracy there in the first place and (c) say what you actually mean.
Of course you can speculate on whatever you like. Of course what you suggest would be one possible reason for the low levels of charges and convictions which you describe.
But you
cannot claim that the low level of charges and convictions
proves that you are right. I am simply pointing out that the nature of the threat means that the police will inevitably intervene earlier and, as a direct result of that (as they well know), that may well mean that there is insufficient evidence to sustain charges, let alone convictions.
If you are saying that people have been arrested where there has been insufficient evidence to justify that action then the main check / balance is the right that an unlawfully arrested person has to take a civil action and / or to make a complaint via IPCC/police. A local community group
could make a complaint via the IPCC/police themselves, too.
Very few other people know (or can be told, where the information is sensitive) what the grounds for arrest are, but the people directly concerned have a legal right to know and to take civil action if they disagree.
Without knowing the actual evidence / intelligence / information on which the arrests were made I cannot say whether or not the individual arrests were justified (and so I don't, I merely suggest that it is unlikely in my opinion, for the reasons posted) and you cannot say whether or they were either (but you do, directly equating the low numbers of charges / convictions with there being insufficient grounds in the first place).