Northwest Frontier was the original British title for Flame Over India. When the Moslems attack a British fortress in colonial India, it is imperative that the local Maharaja's son be taken to safety. The man for the job is commander Kenneth More, who uses a rusty old train for that purpose. Among the other fugitives is the boy's British governess Lauren Bacall and the untrustworthy Herbert Lom. A cat-and-mouse session between good and bad guys segues into a heart-pounding chase through the frontier. Welcome comedy relief is in the hands of I.S. Johar as a grizzled old engineer. It looks like a western and sounds like a western, and the original title Northwest Frontier completes the illusion that we're watching Cowboys and Indians rather than Indians and Moslems.
~ Hal Erickson, All Movie Guide