In the Squad, informality is everything. Everyone calls DCI Haskins simply "Haskins" (except to his face), though Regan occasionally calls him by his first name, Frank. No one ever calls Regan "Mister"—except the villains, or sometimes Carter when talking to Haskins. To the Squad, he is always simply "the Guv'nor", or just "Guv". In turn, he invariably calls Carter and the other Squad members by their first names, or occasionally nicknames. When off duty, he and George Carter are friends and drinking buddies, so in private Carter calls him "Jack". This is all in accordance with widespread police convention.