I see your point, but it really sounds like a useless parity measure to me. does access matter if you can't sustain it for a conflict of any reasonable duration?

Yes because it determines your potential... you can always find a certain number of good soldiers immediately (even if very few) but it takes decades to build industry and tech.

are you sure about this? as you say, half the army would instantly defect to the opposition. what fraction of the others would immediately become pregnant? then theres reserves, how many fighting age non military Brits would actually want to fight this? Not just in some abstract sense but go actually get shot at. For the country and the leaders who created the problem in the first place(among the fuckton of other nasty things).

If the UK government suddenly got based enough to take action and kick out the refugees, there would be no shortage of competent white male volunteers. Authentic, strong leadership galvanizes men, even men that start out weak.