Dear mr Black Adder,
If the only war we are going to fight is at sea, you make a sensible case for amalgamating everything under a dark blue service.
If you think everything will take on land, you make a cogent case for amalgamating everything under a light blue service.
If you believe air power will only be used in the support of the army, you make a sensible case for amalgamating everything under a brown service.
If you believe, in peace time when we do not know when the next threat is coming from, that any one of the three is able or willing to present a totally balanced view....
May I suggest you go stand in the corner and stick two pencils up your nose.
(Lordy, where do they come from, if it was that easy, no one would ever lose a war!!)