A short walk from Wall Street, the US justice department’s southern district of New York office in Manhattan has long been a dominant force in the world of white-collar criminal prosecution.

Often referred to as the “sovereign district” for its pre-eminence, it has brought some of the biggest white- collar cases in recent memory, including prosecutions of insider trader Ivan Boesky, junk bond king Michael Milken, executives at WorldCom and Adelphia, and lifestyle media mogul Martha Stewart.