ATC historian John Platt has tracked down the first publication of the "United Kingdom Air Pilot" to November 1924. It was certainly known as the Air Pilot in the late 1960s and pretty sure that was actually printed on the cover(s). There were three volumes then. I believe it was renamed the Aeronautical Information Publication in the 1970s but the Air Pilot name stuck. As new generations of ATCO's/ATCs take over it will no doubt disappear.