If you want to keep a topic on thread (in any internet forum) simply ignore trolls/trolling, or just be polite/apologetic about digression.
On topic...circa 2010 Stephanie Flaunders, then BBC economics lead journo, wrote a piece re "socially impossible budget cuts" (sorry the link has gone).
Her point being, back in 2010, the level of cuts required to balance the books were simply to big for society to except - ergo they were not achievable and would not happen. She was 100% correct. She said we would get austerity lite plus smoke and mirrors.
I suggest, we are still in the same place, and specifically cutting defence by such a large amount will prove politically challenging. That said, defence is in for a rough time whatever happens.
Off topic...the UK general election is due in a little over 5 months and every political party is committed to balancing the books and austerity in some form or other, so lets be realistic hey.