From 1963 to 1970, Tully was the principal writer on Steel Claw for Valiant with artist Jesús Blasco, taking over for the fourth serial from Ken Bulmer, and later returning from 1971 to 1973 for the sequel strip, Return of the Claw. He also worked on Kelly's Eye and Janus Stark, and wrote Heros the Spartan with art by Frank Bellamy for Eagle. According to the first printing Paul Scoones's The Comic Strip Companion (2012), Tully was also regular writer on the Doctor Who strip in TV Comic prior to 1966; however subsequent research suggests that the author had confused Tully with another comics writer of this period, Thomas Woodman.