Flower I suspect you are misenterpreting VA's comment, which I believe was about the OnTrack project rather than about the Kemble AIC.
VA
As most infringements result from pilot related problems, it was important to commission a project team of non-CAA active pilots, to discuss infringements inconfidence with pilots and controllers, without fear of punitive action. The selection
of suitable team members was critical to the success of the project. It was essential they had collective experience of both GA pilot and controller operational issues and also had inter-personal skills that would encourage reporters to feel comfortable
when discussing sensitive events.
Note that the OnTrack team were not from the CAA and also not from ATC.
ATC were free to provide input, as were pilots. It was the job of the project team to collate and evaluate the information they received (and there was a lot of it) and this report is the result. It was not the job of the team to express or impose their own personal views. In collating information from pilots and controllers it was important that they were not "officials" either from the CAA or from the controller community. A controller may have felt inhibited about speaking his mind if he knew that he would be personally identifiable to a person in a position of authority, perhaps even from within the same organisation he works for.
As the quote above says, infringements generally stem from pilots. The project was trying to find the causal factors that led pilots to infringe. While controllers have to deal with the problem when it arises, they appear to be rarely involved in the factors that led to the infringement.
As I recall, there was actually quite a lot of input from controllers in the discussion.
Mike