A file of reports, memoranda, and correspondence concerning relations between the Security Service (MI5) and the Secret Intelligence Service (MI6) after the Second World War. The documents include a report from a working party investigating relations between the two services, and letters negotiating the division of responsibilities. The main subjects of contention were permission for MI5 to operate abroad, the responsibility for collection and collation of intelligence, and liaison arrangements and the proposal that both services move into a new shared headquarters building in London.