An Englishman's Castle (1978)

The story is set in an alernate 1970's, on an Earth where Germany won WWII and has occupied England. Peter Ingram is a writer on a popular soap opera (also titled "An Englishman's Castle) that is set in London during the Blitz. Ingram lives a quiet, boring life, deliberately oblivious to the subtle rule of the local Nazis. His eyes are opened when the woman he is involved with reveals that she is both a Jew and a member of the Underground. Will Peter help overthrow his countries oppressors?