Aut cum scuto aut in scuto
"P FOR PAPA" Would be the standard call sign in the WW2 RAF. That's a fairly short range night "intruder" A-20. They were replaced later by the DH-4 Mosqito (spell?) night intruders---Ray
In the RAF during WWII, there were three letters on each side of the fuselage. The first two were the squadron code and the third was the aircraft designator. On the left side the squadron code (YP for 23rd squadron) is in front of the roundel. Since there is no room for the P behind the roundel it was painted on the front. In the RAF phonetic language it was P for Poisin. The letters were used to sort out formations, the Luftwaffe used various markings such as yellow noses or mascots while the USAAF used brightly coloured tails for the same purpose. Al_in_Ottawa
You may not have noticed but there's a giant K on the tails of some of the B-52G models that sat at Davis Monthan AFB after the big draw after the first Great Oil War. The K was for Kimbolton. The bombers belonged to a squadron that had been based out of there in WWII. The 524th Bomb Squadron, 379th Bomb Wing, Wurtsmith AFB, Mi.