 The first member of the class was given a livery of plain black without lining; this was changed to the new standard British Railways Brunswick green that was applied to express passenger locomotives after nationalisation, despite the locomotive being classed as mixed traffic. This was lined in orange and black, and the class was given the power classification 7MT. The "Britannias" were numbered under the new British Railways standard numbering system in the 70xxx series. The locomotives were numbered between 70000 and 70054, and featured brass nameplates with an initial black background, followed by red, located on the smoke deflectors. Towards the end of steam plain green livery was substituted, with the touching-up of existing paintwork being preferred to full aesthetic overhaul.
