The article considers the lexical units of Modern British English which have entered the common use from regional and social dialects. The aim of the study is to find out whether regional and social lexemes undergo additional pejorative sense development while shifting from non-standard language forms to standard British English. The data for the research has been extracted from “The Oxford English Dictionary”. It is stated that within the period of the XVI—XX cc. the regional dialects of Great Britain didn’t contribute a lot to enriching pejorative lexis. The lexemes from the social dialects entered the Standard English language mostly within the period of the XIX—XX cc. with the tendency to their growth in the second half of the XX c. The conclusion is made that in most cases regional and social units have functioned as pejorative means before they enter the common use so that they don’t acquire additional pejorative sense development in the standard language.