Originally intended to be written by William Walton, the score is predominantly the work of Ron Goodwin, with Walton's "Battle in the Air" sequence and screen-credits coda included. apparently to mollify Walton's friend Sir Laurence Olivier. who portrayed RAF Fighter Command chief Air Marshal Sir Hugh Dowding in the film.
Rip of a CD apparently made using the soundtrack master, with some "sweetening" added here and there by engineer Eric Tomlinson. Judging by the excellent sonics, he did good. :-)