As I just posted on ARRSE - well, smaller isn't the answer, just a reallocation of resources. As an island, the Navy is the main source of defence - which is how it needs to be, trident guarantees pretty much our safety as a nation, and we can't afford long term ground deployments, so why need a big army? Shrink it, become an amphibious ops driven force and that can be our 'party piece'
The General Leakey quoted is obviously a typically dim brown job who thinks entirely in the present and of elective wars like the current one. If we alone were to be attacked, that is to say to have a war forced upon us, I see no evidence that any of our so-called allies would lift a finger for us.