Because the British Diptera fauna has undergone considerable study and revision, there has been an increased need for a new check list. The last treatment dates back to 1976 (Kloet & Hincks 1976) and listed 5997 species. The current list includes 6668 valid species, with another 690 "nomina dubia", 193 "excluded species" and 16 imported species. Another 55 British species, awaiting confirmation of their identity or description as new, are referred to in the Notes, but are not included in the totals.