The UK is a country of only 60 million or so souls and has long punched above it's weight in international affairs even with the disappearance of it's empire. They cannot afford to keep up their spending the way they have and their armed forces are taking some cuts. They are no longer the guarantor of keeping the seas free and have not been for a long time, even if they doubled their defence budget they would still only have a fraction of the forces the US has. It's the real world, not a yellow brick road or gold-paved street. Fortunately for the Brits their current leadership seems to have a good grasp of that reality.