Had some interesting thoughts come up with my continuing conversation with YorkAnon, my north UK friend.
We know FISA is tied with British intelligence. They provided lots of support for the treasonous campaign against POTUS. When that comes out, it will put the UK in a brutal spot diplomatically, where they tried to assist in the overthrow of a lawfully elected US president.
The UK government is being forced by its people to go through with Brexit, which will sever them economically from the EU. With May's deal being rejected, it looks like hard Brexit is the new order of the day.
Put that together, and potentially you have the UK divided from all its allies, and isolated. When FISAgate is exposed, its game over for the DS in the UK. This could explain why May is working so hard to kick the can down the road with brexit, because her government is about to lose all its trade and military partners.
TL;DR: theory is that FISA and brexit together destroy the DS in the UK.