Ferrar opted to move to join the Home Department of the Government of India in 1901 [1] and was inducted into the Punjab Commission.
[3] Before becoming Commissioner of the Andaman and Nicobar Islands he served at various positions in northern and northwestern parts of British India.
From 1902-1906 he commanded the Baloch Levy, was a postal censor at Bombay, 1915-18, and deputy commissioner Lahore, 1919-23, during which time he was involved in the arrest of Lala Lajpat Rai and Satyanand Stokes on charges of sedition.
[5][6] He initiated measures to protect fishing grounds in the Andamans from being poached by Singapore fishermen for Trochus shells.
[8][5] A keen naturalist and student of the butterfly fauna,[10][11] he collected over 4000 specimens which are now in the Natural History Museum at London.