IMO there will be no FULL disclosure.
Think of it like this. A British government finally decides to to tell a blinkerd/dumbed down population that other countries exist and 'foreigners' are real, they've even been coming here on holiday.
What they won't tell us is that they have been 'dealing' with the governments of foreign countries sharing some secrets and witholding other secrets etc.
We know foreigners 'exist' but we don't know their secrets, and probably never will. Least of all their government's secrets.
norman.