<prompt> Bhala ukuqhubeka kwalesi sigaba - Wabuyela ebuthweni lempi ngaphambi kweMpi Yezwe II, waqokwa njengomphathi wamabutho eRoyal Air Force Volunteer Reserve ngomhlaka 25 Ephreli 1939. NgoJuni 17, 1940, kulandela isimemezelo sikaMarshal Philippe Pétain ngenhloso yakhe yokufuna ukuthula  <response>: , I-Air-Vice Marshal u-Arthur Barratt, isikhulu se-Air Commanding-in-Chief amabutho aseBrithani eFrance, wathumela uGrinell-Milne ohambweni lokuletha izincwadi kubaholi be-French Air Force, echaza ukuzimisela kweBrithani ukuqhubeka nokulwa, futhi ebakhuthaza ukuba benze okufanayo eNyakatho Afrika. UGrinnell-Milne waphinde wamiswa njengomphathi wokuxhumana waseBrithani kuMkhuzi Omkhulu Wezempi Yezindiza zaseFrance uJoseph Vuillemin, futhi wahlonyiswa ngesidlulisi somsakazo esiphathwayo, izimpawu zokubiza kanye namakhodi. UGrinnell-Milne waya eBordeaux, wabe eseya e-GHQ ye-French Air Forces e-Agen. Lapho uVuillemin wazisa ngokudabukisayo ukuthi wayeqale inqubo yokudlulisela amadoda nezindiza eNyakatho Afrika, kodwa manje wayethole imiyalo yokumisa konke ukuhamba. UGrinnell-Milne wathola ukuthi iningi lamaphoyisa aphakeme lalisenkingeni, liphazamisa, noma lihlasela ngokusobala, yize ephawule ukuthi iningi lamaphoyisa amasha namadoda lalinesifiso sokuya eNgilandi. Washiya iFrance ngoJuni 18 sekwephuzile. Lapho esebuyele eLondon wamiswa njengesikhulu esixhumanisa neFree French General uCharles de Gaulle, wahlala naye izinyanga ezine ezalandela, futhi wabamba iqhaza ezimpini zaseDakar naseGabon. Wakhushulwa waba ngumshayeli wendiza ngomhlaka 3 Agasti 1941. UGrinnell-Milne wakhululwa e-RAF ngokobuchwepheshe wasula esikhundleni sakhe, wagcina isikhundla sakhe sokuba ngumshayeli wendiza ngomhlaka 20 Julayi 1944. Ngemva kwalokho wabuyela ku-BBC, wahlala lapho kwaze kwaba ngo-1946. 