▁on ▁the ▁Cambridge ▁University ▁East ▁Green land ▁Ex ped ition ▁of ▁ 1 9 2 6 ; ▁when ▁he ▁returned , ▁he ▁took ▁up ▁the ▁post ▁of ▁Cas ual ty ▁Officer ▁at ▁the ▁Metropolitan ▁Hospital ▁in ▁London . ▁In ▁ 1 9 2 7 ▁he ▁was ▁House ▁Phys ician ▁at ▁the ▁East ▁London ▁Hospital ▁for ▁Children . ▁In ▁ 1 9 2 8 , ▁his ▁love ▁of ▁travel ▁having ▁again ▁taken ▁him ▁away ▁from ▁Britain , ▁he ▁was ▁Medical ▁Officer ▁to ▁the ▁Harr ington ▁Har bour ▁Hospital ▁in ▁Quebec , ▁which ▁was ▁run ▁by ▁the ▁International ▁Gren f ell ▁Association , ▁a ▁char ity . ▁ ▁Johnson ▁returned ▁to ▁become ▁a ▁General ▁Pract ition er ▁at ▁Thor nt on ▁He ath ▁in ▁Cro yd on , ▁south ▁London , ▁from ▁ 1 9 3 0 . ▁In ▁that ▁year ▁he ▁was ▁also ▁called ▁to ▁the ▁Bar , ▁although ▁he ▁never ▁pract ised . ▁He ▁became ▁interested ▁in ▁politics ▁and ▁active ▁in ▁the ▁Liberal ▁Party , ▁and ▁in ▁the ▁ 1 9 3 5 ▁general ▁election ▁he ▁was ▁the ▁Liberal ▁Party ' s ▁candidate ▁in ▁B ury . ▁ ▁By - e lection ▁candidate ▁In ▁ 1 9 3 6 ▁Johnson ▁retired ▁from ▁full - time ▁work ▁to ▁dev ote ▁himself ▁to ▁politics . ▁In ▁May ▁ 1 9 3 7 ▁he ▁was ▁chosen ▁as ▁the ▁Liberal ▁candidate ▁at ▁the ▁Bew d ley ▁by - e lection , ▁caused ▁after ▁Prime ▁Minister ▁Stanley ▁Bald win ▁retired ▁and ▁was ▁given ▁a ▁Pe er age .