[ted angus]

From the photo evidence, units issued with warning orders for service with the Air Component Field Force would possibly have commenced camo painting late july /early August 1939, whilst most of the warned units embarked for France some didn't. General Alert was called about a week before the famous speech. From what I have read in Operational Order Books, Station and Sqn war books contained lists of measures to be initiated as the alert state went up. I would think camo painting would have been one along with aircraft dispersal, sandbagging, opening and equiping shelters etc etc. So my best guess is it commenced on non Field Force units in the weeks or week prior to declaring war.
Larry you use the word "Frontline"; as far as the RAF in UK was concerned it is difficult to quantify frontline; we could say Biggin Hill North Weald etc etc. most publications say the south east of England was the frontline, but this is something else I don't fully subscribe to. Turnhouse and Drem were the first frontline units as German based ac attacked their sectors in a bid to hit Rosyth and of course the protecting aerodromes. In addition the RAF crane on a 42 Group Maintenance Command Maintenance Unit loading bombs, oxygen cylinders and fuel into railway waggons for delivery to the operational aerodromes was to me as big a target as many airfields and therefore equally frontline in the context we are mulling over. . Even the barrage balloon winch trucks seem to have received a lick of camo very early on. I wish I could spend a month at Kew and Hendon and with the air historical branch; when the answers are found I don't think it will be a "tell all" document but it will be a one sentence comment in something like a Station or Sqn operations log that will reveal some key parts of the jigsaw.
Regards
TED