My point is that politicians respond to the messages they get from the electorate - there is no popular support for spending on defence in the UK right now
If any party was to stand on the basis that
" we're going to increase the military budget and increase taxes"or
"we're going to increase the military budget and cut the NHS/pensions/Education"
they'd be reduced to a couple of dozen seats
Sad but in general the good people of the UK don't feel threatened right now - certainly not by nuclear or conventional foreign forces - maybe by Al Qaeda
TBH this is how Churchill spent years in the wilderness - no-one wanted to listen to his warnings