Armed Forces Federation
I can't find (quickly) the original thread and the case that Lord Garden made for a single tri-service, all-ranks, federation.
Etheral entitiy makes the same, or similar case. I disagree and believe that several associations or federations might be better.
True, a single all embracing federation can speak with one voice.
The problem, as I see it, is how that one voice is arrived at. You would be seeking a consensus between 3 different services and 3 or 4 sectors of each service - senior and middle management, SNCOs, and others. The board would have to be large to convince each sector that its interests are being properly represented.
The senior management sector should, if properly promoted, be the predominant and 'leve-headed' group and thus potentially dominate and consensus and subsequent discussion.
If each sector was a separate organisation then each could chose its representative and reach consensus within its own group. Each group could then combine to produce an overal or enlarged consensus but more importantly it could present a dissenting view.
Examples include the medical profession with Royal College of Nursing, the GMC, the surgeons etc. The rank and file police had a federation and the chief constables have a separate one.
Within the MOD the civil service has 4 separate groups, First Class, Prospect, PCS, and the ROA. Each can represent its own group to its own rules and avoid accusations of bipartisanship from a disparate membership.
Perversely I suspect that one single tri-service, all-ranks federation would be vulnerable to divide and rule far more so that single-service, officers-ranks associations. Each separate organisation could still form a higher level association much as Prospect and PCS do when it comes to pay bargainng.