Sentence:  It is one of the national peccadilloes that anyone who lives north of St. Albans has some kind of prejudice against Londoners — perhaps "prejudice" is the wrong word — or rather not against Londoners but against <WSD>southernism</WSD>. 
Meaning of the word marked with <WSD> tags:  Anything characteristic of the southern part of a region, especially the southern United States.