In RAF AD up to about 2000 port and starboard were used for commands and left and right for target information.
e.g. as I have target 35 left heading 270, starboard 090 for 180 displaced left.
The reason being that, during comms jamming, the pilots could differentiate between orders and instructions.
The USA and others only used Left and Right so, as we increasingly operated in combined Ops we followed their terminology.
The RN of course favoured the use of green and red for clearing approaches and overflights - resulting in the apocryphal RAF question, is that from the sharp end or the blunt end?
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