Come friendly bombs and fall on Abbey Wood | Kings of War
It just so happens that for an accumulation of reasons, the British peoples have a comparative advantage when it comes to fielding and leading highly effective military forces. This may seem entirely counter intuitive to people who view them, especially the English, as polite tolerant and courteous to a fault. Others, the French Spanish and Germans for example, have historically made much more of a public display of their tradition of bellicose masculinity. However in war above all other things results matter.
The fact is that 100 years of experimenting with incremental Socialism have proven that the British are simply not good at it. Perhaps somewhere there is an isolated and homogeneous society that will prove amenable to centralized bureaucratic administration and that will yield a high rate of productivity under the such a regime. No one has found such a community and if the North Koreans can't pull it off then maybe no one can.
So here we have a situation where you can do something better than other people can and do something else no better than or even worse than other people can. It does not seem very hard to say what your rational choice should be. Fire not just 20,000 civilians from the MoD but another 2.50,000 tax eaters infesting the landscape and free yourselves from the administrative leash of Brussels. Do that and you will be able to double your armed forces, while increasing your national wealth.
How large should the military be? It should be possible for a healthy society to maintain an efficient military establishment when not engaged in existential general conflict with an expenditure of about 4-4.5% of GDP. That should enable you to keep approximately 3% of the population between 18 and 40 years old under arms on active duty with thrice that as trained reserves earning superior education and health benefits. The UK has about 6 million residents between 18 and 24 year old (source: National Statistics Office). It would be reasonable to expect 10% of them to be serving at any time. Would this be a larger forces structure than is now supported? Yes but not outrageously large in historical terms. Is there a reason to support a force of that size? Ask yourself this question. Are there threats and insults to yourself or your allies ignored because the Prime Minister lacks the tools to deal with them? Are there bullies thieves and homicidal criminals who extort wealth or threaten your nationals or interfere in your domestic institutions with impunity because they do not fear you?
If what you want is a safe peaceful world where your people can travel and conduct their business inoffensively and in safety and where outside potentates will not send money and agents to undermine your institutions then shift your priorities and deconstruct the welfare state while rebuilding the armed forces that you are so good at.With luck and if the model of the Royal Navy that kept the peace for decades holds true you will be able to build it and rarely use it. That will prove that you built it large enough.