That was the team: the group of five. In time it expanded, but to start with, these five alone made up the famous cadre, and to have been one of them, said [one of the five] afterwards, was "like holding a Communist Party card with a single-figure membership number."

from "The Honourable Schoolboy" by John Le Carre.

All five are members of fictional British Intelligence during Cold War trying to rebuild the service betrayed by a traitor a la Kim Philby.